Systems and methods for feedback reporting

ABSTRACT

A User Equipment (UE) is described. The UE decodes an uplink/downlink (UL/DL) reconfiguration downlink control information (DCI) with an enhanced interference mitigation with traffic adaptation (eIMTA)-radio network temporary identifier (RNTI) on a physical downlink control channel (PDCCH). The UE also determines if one or more valid UL/DL configurations in the UL/DL reconfiguration DCI with eIMTA-RNTI for all configured eIMTA cells are received. The UE further determines if physical uplink control channel (PUCCH) format 3 is configured. The UE additionally determines a PUCCH resource for physical downlink shared channel (PDSCH) hybrid automatic repeat request acknowledgement/negative acknowledgement (HARQ-ACK) reporting based on whether valid UL/DL configurations in the UL/DL reconfiguration DCI with eIMTA-RNTI for all of the configured eIMTA cells corresponding to a subframe for the PUCCH resource are received. The UE also sends PDSCH HARQ-ACK information on the selected PUCCH resource in an uplink subframe.

TECHNICAL FIELD

The present disclosure relates generally to communication systems. Morespecifically, the present disclosure relates to systems and methods forfeedback reporting.

BACKGROUND

Wireless communication devices have become smaller and more powerful inorder to meet consumer needs and to improve portability and convenience.Consumers have become dependent upon wireless communication devices andhave come to expect reliable service, expanded areas of coverage andincreased functionality. A wireless communication system may providecommunication for a number of wireless communication devices, each ofwhich may be serviced by a base station. A base station may be a devicethat communicates with wireless communication devices.

As wireless communication devices have advanced, improvements incommunication capacity, speed, flexibility and/or efficiency have beensought. However, improving communication capacity, speed, flexibilityand/or efficiency may present certain problems.

For example, wireless communication devices may communicate with one ormore devices using a communication structure. However, the communicationstructure used may only offer limited flexibility and/or efficiency. Asillustrated by this discussion, systems and methods that improvecommunication flexibility and/or efficiency may be beneficial.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating one configuration of one or moreevolved Node Bs (eNBs) and one or more user equipments (UEs) in whichsystems and methods for feedback reporting may be implemented;

FIG. 2 is a flow diagram illustrating one implementation of a method forfeedback reporting by a UE;

FIG. 3 is a flow diagram illustrating one implementation of a method forfeedback reporting by an eNB;

FIG. 4 is a diagram illustrating one example of a radio frame that maybe used in accordance with the systems and methods disclosed herein;

FIG. 5 is a diagram illustrating time-division duplexing (TDD)uplink/downlink (UL/DL) configurations in accordance with the systemsand methods described herein;

FIG. 6 is a flow diagram illustrating another implementation of a methodfor feedback reporting by a UE;

FIG. 7 is a flow diagram illustrating one implementation of a method forfeedback reporting by a UE while in a normal mode of operation;

FIG. 8 is a flow diagram illustrating one implementation of a method forfeedback reporting by a UE while in a fallback mode of operation;

FIG. 9 illustrates various components that may be utilized in a UE;

FIG. 10 illustrates various components that may be utilized in an eNB;

FIG. 11 is a block diagram illustrating one configuration of a UE inwhich systems and methods for feedback reporting may be implemented; and

FIG. 12 is a block diagram illustrating one configuration of an eNB inwhich systems and methods for feedback reporting may be implemented.

DETAILED DESCRIPTION

A user equipment (UE) is described. The UE includes a processor andmemory in electronic communication with the processor. The UE decodes anuplink/downlink (UL/DL) reconfiguration downlink control information(DCI) with an enhanced interference mitigation with traffic adaptation(eIMTA)-radio network temporary identifier (RNTI) on a physical downlinkcontrol channel (PDCCH). The UE also determines if one or more validUL/DL configurations in the UL/DL reconfiguration DCI with eIMTA-RNTIfor all configured eIMTA cells are received. The UE further determinesif physical uplink control channel (PUCCH) format 3 is configured. TheUE additionally determines a PUCCH resource for physical downlink sharedchannel (PDSCH) hybrid automatic repeat request acknowledgement/negativeacknowledgement (HARQ-ACK) reporting based on whether valid UL/DLconfigurations in the UL/DL reconfiguration DCI with eIMTA-RNTI for allof the configured eIMTA cells corresponding to a subframe for the PUCCHresource are received. The UE also sends PDSCH HARQ-ACK information onthe selected PUCCH resource in an uplink subframe.

If PUCCH format 3 is configured and valid UL/DL configurations in theUL/DL reconfiguration DCI with eIMTA-RNTI for all of the configuredeIMTA cells corresponding to a subframe for the PUCCH resource arereceived, then the UE may determine the PDSCH HARQ-ACK information basedon at least one of a DL subframe and a special subframe according to theUL/DL configuration in the UL/DL reconfiguration DCI in a DL associationset for a given UL subframe of each configured eIMTA cell.

If PUCCH format 3 is configured and one or more valid UL/DLconfigurations in the UL/DL reconfiguration DCI with eIMTA-RNTI for atleast one of the one or more configured eIMTA cells corresponding to asubframe for the PUCCH resource is not received, then the UE maydetermine the PDSCH HARQ-ACK information based on at least one of a DLsubframe and a special subframe according to a system information blocktype 1 (SIB1) configuration in a DL association set according to a DLHARQ reference configuration for a given UL subframe of each configuredeIMTA cell. The SIB1 configuration may include a UL/DL configuration inSIB1 signaling or RadioResourceConfigCommon signaling when a configuredeIMTA cell is a primary cell (PCell). The SIB1 configuration may includea UL/DL configuration in RadioResourceConfigCommonSCell-r10 signalingwhen a configured eIMTA cell is a secondary cell (SCell).

If PUCCH format 3 is configured and a valid UL/DL configuration in theUL/DL reconfiguration DCI with eIMTA-RNTI for at least one configuredeIMTA cell corresponding to a subframe for the PUCCH resource is notreceived, then the UE may determine the PDSCH HARQ-ACK information basedon a DL association set according to a DL HARQ reference configurationfor a given UL subframe of each configured eIMTA cell.

If valid UL/DL configurations in the UL/DL reconfiguration DCI witheIMTA-RNTI of all configured eIMTA cells corresponding to a subframe forthe PUCCH resource are received, then the UE may determine the PUCCHresource based on at least one of a Transmitter Power Control (TPC)field and an acknowledgment resource offset (ARO). If a PDSCH isdetected on an SCell in a DL assignment by PDCCH/enhanced physicaldownlink control channel (EPDCCH), or a downlink assignment index (DAI)value is greater than 1 in a detected PDCCH on a primary cell (PCell),then the UE may determine a PUCCH format 3 resource based on a TPC fieldin a PDCCH/EPDCCH assignment with a DAI value greater than 1. If thereis no PDSCH detected on an SCell and a DAI value is greater than 1 in adetected EPDCCH on a PCell, then the UE may determine a PUCCH format 3resource based on a HARQ-ACK resource offset field in a DCI format of acorresponding EPDCCH assignment with a DAI value greater than 1. Ifthere is only one PDSCH detected with a DAI value of 1, excludingsemi-persistent scheduling (SPS) on a PCell, then the UE may determine aPUCCH format 1a/1b resource based on the number of control channelelements (CCE).

If at least one valid UL/DL configuration in the UL/DL reconfigurationDCI with eIMTA-RNTI for at least one configured eIMTA cell correspondingto a subframe for the PUCCH resource is not received, then the UE maydetermine the PUCCH resource based on at least one of a predefinedoffset or a separate PUCCH resource. If a PDSCH is detected on an SCellin a DL assignment by PDCCH/EPDCCH, or a DAI value is greater than 1 ina detected PDCCH on a PCell, then the UE may determine a PUCCH format 3resource based on a predefined offset or a separate PUCCH resource and aTPC field in a PDCCH/EPDCCH assignment with a DAI value greater than 1.If there is no PDSCH detected on an SCell and a DAI value is greaterthan 1 in a detected EPDCCH on a PCell, then the UE may determine aPUCCH format 3 resource based on at least one of a predefined offset ora separate PUCCH resource and a HARQ-ACK resource offset field in a DCIformat of a corresponding EPDCCH assignment with a DAI value greaterthan 1. If there is only one PDSCH detected with a DAI value of 1,excluding SPS on a PCell, then the UE may determine a PUCCH format 1a/1bresource based on the number of CCEs.

If valid UL/DL configurations in the UL/DL reconfiguration DCI witheIMTA-RNTI for all of the configured eIMTA cells corresponding to asubframe for the PUCCH resource are received, then the UE may determinethe PUCCH resource based on at least one of a predefined offset or aseparate PUCCH resource. If a PDSCH is detected on an SCell in a DLassignment by PDCCH/EPDCCH, or a DAI value is greater than 1 in adetected PDCCH on a PCell, then the UE may determine a PUCCH format 3resource based on at least one of a predefined offset or a separatePUCCH resource and a TPC field in a PDCCH/EPDCCH assignment with a DAIvalue greater than 1. If there is no PDSCH detected on an SCell and aDAI value is greater than 1 in a detected EPDCCH on a PCell, then the UEmay determine a PUCCH format 3 resource based on at least one of apredefined offset or a separate PUCCH resource and a HARQ-ACK resourceoffset field in a DCI format of a corresponding EPDCCH assignment with aDAI value greater than 1. If there is only one PDSCH detected with a DAIvalue of 1, excluding SPS, on a PCell, then the UE may determine a PUCCHformat 1a/1b resource based on the number of CCEs.

If at least one valid UL/DL configuration in the UL/DL reconfigurationDCI with eIMTA-RNTI for at least one configured eIMTA cell correspondingto a subframe for the PUCCH resource is not received, then the UE maydetermine the PUCCH resource based on at least one of a TPC field and anARO. If a PDSCH is detected on an SCell in a DL assignment byPDCCH/EPDCCH or a DAI value is greater than 1 in a detected PDCCH on aPCell, then the UE may determine a PUCCH format 3 resource based on aTPC field in a PDCCH/EPDCCH assignment with a DAI value greater than 1.If there is no PDSCH detected on an SCell and a DAI value greater than 1in a detected EPDCCH on a PCell, then the UE may determine a PUCCHformat 3 resource based on a HARQ-ACK resource offset field in a DCIformat of a corresponding EPDCCH assignment with a DAI value greaterthan 1. If there is only one PDSCH detected with a DAI value of 1,excluding SPS, on a PCell, then the UE may determine a PUCCH format1a/1b resource based on the number of CCE.

An evolved node B (eNB) is also described. The eNB includes a processor;and memory in electronic communication with the processor. The eNBtransmits, to a UE, UL/DL reconfiguration DCI with an eIMTA-RNTI on aPDCCH. The eNB also assumes that the UE determines if one or more validUL/DL configurations in the UL/DL reconfiguration DCI with eIMTA-RNTIfor all of the configured eIMTA cells are received. The eNB furtherassumes that the UE determines if PUCCH format 3 is configured. The eNBadditionally assumes that the UE determines a PUCCH resource for PDSCHHARQ-ACK reporting based on whether valid UL/DL configurations in theUL/DL reconfiguration DCI with eIMTA-RNTI for all of the configuredeIMTA cells corresponding to a subframe for the PUCCH resource isreceived. The eNB also monitors potential PUCCH resources and receivesPDSCH HARQ-ACK information on the detected PUCCH resource in an uplinksubframe.

If PUCCH format 3 is configured and valid UL/DL configurations in theUL/DL reconfiguration DCI with eIMTA-RNTI for all of the configuredeIMTA cells corresponding to a subframe for the PUCCH resource arereceived by the UE, then the eNB may assume that the UE determines thePDSCH HARQ-ACK information based on at least one of a DL subframe and aspecial subframe according to the UL/DL configuration in the UL/DLreconfiguration DCI in a DL association set for a given UL subframe ofeach configured eIMTA cell.

If PUCCH format 3 is configured and one or more valid UL/DLconfigurations in the UL/DL reconfiguration DCI with eIMTA-RNTI for atleast one of the one or more configured eIMTA cells corresponding to asubframe for the PUCCH resource is not received by the UE, then the eNBmay assume that the UE determines the PDSCH HARQ-ACK information basedon at least one of a DL subframe and a special subframe according to aSIB1 configuration in a DL association set according to a DL HARQreference configuration for a given UL subframe of each configured eIMTAcell. The SIB1 configuration may include a UL/DL configuration in SIB1signaling or RadioResourceConfigCommon signaling when a configured eIMTAcell is a PCell. The SIB1 configuration may include a UL/DLconfiguration in RadioResourceConfigCommonSCell-r10 signaling when aconfigured eIMTA cell is an SCell.

If PUCCH format 3 is configured and a valid UL/DL configuration in theUL/DL reconfiguration DCI with eIMTA-RNTI for at least one configuredeIMTA cell corresponding to a subframe for the PUCCH resource is notreceived by the UE, then the eNB may assume that the UE determines thePDSCH HARQ-ACK information based on a DL association set according to aDL HARQ reference configuration for a given UL subframe of eachconfigured eIMTA cell.

If valid UL/DL configurations in the UL/DL reconfiguration DCI witheIMTA-RNTI of all configured eIMTA cells corresponding to a subframe forthe PUCCH resource are received by the UE, then the eNB may assume thatthe UE determines the PUCCH resource based on at least one of a TPCfield and an ARO. If a PDSCH is detected, by the UE, on an SCell in a DLassignment by PDCCH/EPDCCH, or a DAI value is greater than 1 in adetected PDCCH on a PCell, then the eNB may assume that the UEdetermines a PUCCH format 3 resource based on a TPC field in aPDCCH/EPDCCH assignment with a DAI value greater than 1. If there is noPDSCH detected, by the UE, on an SCell and a DAI value is greater than 1in a detected EPDCCH on a PCell, then the eNB may assume that the UEdetermines a PUCCH format 3 resource based on a HARQ-ACK resource offsetfield in a DCI format of a corresponding EPDCCH assignment with a DAIvalue greater than 1. If there is only one PDSCH detected, by the UE,with a DAI value of 1, excluding SPS on a PCell, then the eNB may assumethat the UE determines a PUCCH format 1a/1b resource based on the numberof CCEs.

If at least one valid UL/DL configuration in the UL/DL reconfigurationDCI with eIMTA-RNTI for at least one configured eIMTA cell correspondingto a subframe for the PUCCH resource is not received by the UE, then theeNB may assume that the UE determines the PUCCH resource compriseinstructions executable to assume that the UE determines the PUCCHresource based on at least one of a predefined offset or a separatePUCCH resource. If a PDSCH is detected, by the UE, on an SCell in a DLassignment by PDCCH/EPDCCH, or a DAI value is greater than 1 in adetected PDCCH on a PCell, then the eNB may assume that the UEdetermines a PUCCH format 3 resource based on a predefined offset or aseparate PUCCH resource and a TPC field in a PDCCH/EPDCCH assignmentwith a DAI value greater than 1. If there is no PDSCH detected, by theUE, on an SCell and a DAI value is greater than 1 in a detected EPDCCHon a PCell, then the eNB may assume that the UE determines a PUCCHformat 3 resource based on at least one of a predefined offset or aseparate PUCCH resource and a HARQ-ACK resource offset field in a DCIformat of a corresponding EPDCCH assignment with a DAI value greaterthan 1. If there is only one PDSCH detected, by the UE, with a DAI valueof 1, excluding SPS on a PCell, then the eNB may assume that the UEdetermines a PUCCH format 1a/1b resource based on the number of CCEs.

A method performed by a UE is also described. The method includesdecoding an UL/DL reconfiguration DCI with an eIMTA-RNTI on a PDCCH. Themethod also includes determining if one or more valid UL/DLconfigurations in the UL/DL reconfiguration DCI with eIMTA-RNTI for allconfigured eIMTA cells are received. The method further includesdetermining if PUCCH format 3 is configured. The method additionallyincludes determining a PUCCH resource for PDSCH HARQ-ACK reporting basedon whether valid UL/DL configurations in the UL/DL reconfiguration DCIwith eIMTA-RNTI for all of the configured eIMTA cells corresponding to asubframe for the PUCCH resource are received. The method also includessending PDSCH HARQ-ACK information on the selected PUCCH resource in anuplink subframe.

A method performed by an eNB is also described. The method includestransmitting, to a UE, UL/DL reconfiguration DCI with an eIMTA-RNTI on aPDCCH. The method also includes assuming that the UE determines if oneor more valid UL/DL configurations in the UL/DL reconfiguration DCI witheIMTA-RNTI for all of the configured eIMTA cells are received. Themethod further includes assuming that the UE determines if PUCCH format3 is configured. The method additionally includes assuming that the UEdetermines a PUCCH resource for PDSCH HARQ-ACK reporting based onwhether valid UL/DL configurations in the UL/DL reconfiguration DCI witheIMTA-RNTI for all of the configured eIMTA cells corresponding to asubframe for the PUCCH resource is received. The method also includesmonitoring potential PUCCH resources and receiving PDSCH HARQ-ACKinformation on the detected PUCCH resource in an uplink subframe.

The 3rd Generation Partnership Project, also referred to as “3GPP,” is acollaboration agreement that aims to define globally applicabletechnical specifications and technical reports for third and fourthgeneration wireless communication systems. The 3GPP may definespecifications for next generation mobile networks, systems, anddevices.

3GPP Long Term Evolution (LTE) is the name given to a project to improvethe Universal Mobile Telecommunications System (UMTS) mobile phone ordevice standard to cope with future requirements. In one aspect, UMTShas been modified to provide support and specification for the EvolvedUniversal Terrestrial Radio Access (E-UTRA) and Evolved UniversalTerrestrial Radio Access Network (E-UTRAN).

At least some aspects of the systems and methods disclosed herein may bedescribed in relation to the 3GPP LTE, LTE-Advanced (LTE-A) and otherstandards (e.g., 3GPP Releases 8, 9, 10, 11 and/or 12). However, thescope of the present disclosure should not be limited in this regard. Atleast some aspects of the systems and methods disclosed herein may beutilized in other types of wireless communication systems.

A wireless communication device may be an electronic device used tocommunicate voice and/or data to a base station, which in turn maycommunicate with a network of devices (e.g., public switched telephonenetwork (PSTN), the Internet, etc.). In describing systems and methodsherein, a wireless communication device may alternatively be referred toas a mobile station, a UE, an access terminal, a subscriber station, amobile terminal, a remote station, a user terminal, a terminal, asubscriber unit, a mobile device, etc. Examples of wirelesscommunication devices include cellular phones, smart phones, personaldigital assistants (PDAs), laptop computers, netbooks, e-readers,wireless modems, etc. In 3GPP specifications, a wireless communicationdevice is typically referred to as a UE. However, as the scope of thepresent disclosure should not be limited to the 3GPP standards, theterms “UE” and “wireless communication device” may be usedinterchangeably herein to mean the more general term “wirelesscommunication device.”

In 3GPP specifications, a base station is typically referred to as aNode B, an evolved Node B (eNB), a home enhanced or evolved Node B(HeNB) or some other similar terminology. As the scope of the disclosureshould not be limited to 3GPP standards, the terms “base station,” “NodeB,” “eNB,” and “HeNB” may be used interchangeably herein to mean themore general term “base station.” Furthermore, the term “base station”may be used to denote an access point. An access point may be anelectronic device that provides access to a network (e.g., Local AreaNetwork (LAN), the Internet, etc.) for wireless communication devices.The term “communication device” may be used to denote both a wirelesscommunication device (e.g., UE) and/or a base station (e.g., eNB).

It should be noted that as used herein, a “cell” may be anycommunication channel that is specified by standardization or regulatorybodies to be used for International Mobile Telecommunications-Advanced(IMT-Advanced) and all of it or a subset of it may be adopted by 3GPP aslicensed bands (e.g., frequency bands) to be used for communicationbetween an eNB and a UE. It should also be noted that in E-UTRA andE-UTRAN overall description, as used herein, a “cell” may be defined as“combination of downlink and optionally uplink resources.” The linkingbetween the carrier frequency of the downlink resources and the carrierfrequency of the uplink resources may be indicated in the systeminformation transmitted on the downlink resources.

“Configured cells” are those cells of which the UE is aware and isallowed by an eNB to transmit or receive information. “Configuredcell(s)” may be serving cell(s). The UE may receive system informationand perform the required measurements on all configured cells.“Configured cell(s)” for a radio connection may consist of a primarycell and/or no, one, or more secondary cell(s). “Activated cells” arethose configured cells on which the UE is transmitting and receiving.That is, activated cells are those cells for which the UE monitors thephysical downlink control channel (PDCCH) and in the case of a downlinktransmission, those cells for which the UE decodes a physical downlinkshared channel (PDSCH). “Deactivated cells” are those configured cellsthat the UE is not monitoring the transmission PDCCH. It should be notedthat a “cell” may be described in terms of differing dimensions. Forexample, a “cell” may have temporal, spatial (e.g., geographical) andfrequency characteristics.

The systems and methods disclosed herein describe feedback reportingassociated with enhanced interference mitigation with traffic adaptation(eIMTA) cells. In particular, the systems and methods disclosed hereindescribe feedback for UL/DL reconfiguration signaling. The systems andmethods disclosed herein also describe fallback operations for UEs thatsupport eIMTA if UL/DL reconfiguration signaling is missed or is notdetected correctly. The feedback (e.g., acknowledgement) for UL/DLreconfiguration signaling may ensure the correct understanding betweenan eNB and a UE. It may also reduce the payload on the PUCCH, and mayimprove the reliability and performance of PDSCH hybrid automatic repeatrequest acknowledgement (HARQ-ACK).

It should be noted that eIMTA may also be referred to as dynamic UL/DLreconfiguration. Therefore, a cell that supports eIMTA (e.g., an eIMTAcell) may be referred to as a dynamic UL/DL reconfiguration cell. Asused herein, “the UE is configured with eIMTA” may be referred to as“the UE is configured with a serving cell with dynamic subframe typeconversion,” “the UE is configured with a DL-reference UL/DLconfiguration of the serving cell,” “the UE is configured with aUL-reference UL/DL configuration of the serving cell” or “the UE isconfigured with a DL-reference UL/DL configuration of the serving celland a UL-reference UL/DL configuration of the serving cell.”

In some configurations, eIMTA may be used in LTE TDD networks to enablemore flexible use of spectrum using dynamic UL/DL allocation based ontraffic load. Therefore, some subframes may be flexible and convertible(e.g., a flexible subframe) and may be used as either special, downlinkor uplink as described below. With eIMTA, explicit PHY layer signalingmay be used for UL/DL reconfiguration with a time scale of 10milliseconds (ms) or less. The systems and methods described hereinprovide fallback solutions to improve the reliability and robustness ofeIMTA.

An eIMTA cell is a TDD cell that supports dynamic UL/DL reconfigurationto adapt the traffic load on the cell. In LTE time-division duplexing(LTE TDD), the same frequency band may be used for both uplink anddownlink signals. To achieve different DL and UL allocations (e.g.,traffic ratios) in LTE TDD, seven uplink-downlink (UL/DL) configurationsare given in 3GPP specifications (e.g., 3GPP TS 36.211). Theseallocations can allocate between 40% and 90% of subframes to DL signals.

In some implementations, a system information change procedure is usedto change the UL/DL configuration. This procedure has a long delay, andrequires a cold system restart (e.g., all UEs in a system cannottransmit and receive for a certain period of time in order to disconnectthe UL/DL associations of the old configuration and set up newassociations). It should be noted that a subframe association may bereferred to as a “UL/DL association,” which may include UL-to-DLsubframe associations and DL-to-UL subframe associations. Examples ofassociations include association of a DL subframe (PDCCH) to UL powercontrol in a UL subframe, association of a DL subframe physical DLcontrol channel (PDCCH) to physical UL shared channel (PUSCH) allocationin a UL subframe, associations of acknowledgement and negativeacknowledgement (ACK/NACK) feedback on UL subframe(s) for physicaldownlink shared channel (PDSCH) transmissions in DL subframe(s),association of acknowledgement and negative acknowledgement (ACK/NACK)feedback on a physical hybrid automatic repeat request (HARQ) indicatorchannel (PHICH) or physical downlink control channel (PDCCH) forphysical UL shared channel (PUSCH) transmission(s) in UL subframe(s),etc.

Physical (PHY) layer signaling may be extended to enable dynamicDL-to-UL conversion. For example, a special subframe type 2 may be used,which may be viewed as an extension of a standard special subframe thatis used for DL-to-UL transition. This special subframe type 2 can beused to provide UL transmissions while maintaining existing UL/DLassociations. PHY layer signaling may also include using downlinkcontrol information (DCI) 0/4 downlink formats for PUSCH schedulingfollowing the association timings of a UL-reference UL/DL configuration,and using DCI formats 1/2 and extensions for PDSCH scheduling, etc.

As used herein, a “Release 12 UE” may be a UE that may operate inaccordance with 3GPP Release 12 specifications and possibly subsequentspecifications. A Release 12 UE may be a UE that supports eIMTA.Additionally, as used herein, a “legacy UE” may be a UE that may operatein accordance with earlier (e.g., LTE Releases 8, 9, 10, 11)specifications.

In some implementations, eIMTA may be applied for both DL-to-UL andUL-to-DL reconfiguration or switching. For example, eIMTA allowsapplying one configuration for PDSCH HARQ-ACK timing and applyinganother configuration for PUSCH scheduling and PUSCH HARQ-ACK timing.UEs that support eIMTA may follow these timings based on thecorresponding reference UL/DL configurations in an allowed UL/DLreconfiguration range (e.g., switching region). Legacy UEs may followthe existing associations without any change or knowledge of the dynamicUL/DL reconfiguration. However, the eNB may restrict the legacy UEs insome subframes to maintain backward compatible timing.

The systems and methods disclosed herein provide approaches for applyingPDSCH HARQ-ACK timings for UEs that may operate in accordance withRelease 12 specifications (and beyond) based on different DL-referenceUL/DL configurations. For legacy UEs, impacts and restrictions ofallowing legacy UEs to operate without any modifications to existingtimings are also analyzed herein. Based on an allowed UL/DLreconfiguration range, for example, the PDSCH HARQ-ACK timing may beconfigured differently for UEs that support eIMTA than for legacy UEs. Alegacy UE should assume no HARQ-ACK timing change. However, the eNB mayschedule legacy UEs to avoid potential conflicts.

For UEs that support and are configured with eIMTA cells, the PDSCHHARQ-ACK timing of an eIMTA cell may be based on one reference UL/DLconfiguration, while PUSCH scheduling and PUSCH HARQ-ACK timing of aneIMTA cell may be based on another reference UL/DL configuration. Forexample, the PDSCH HARQ-ACK configuration may follow a first referenceUL/DL configuration with a number (e.g., minimum number) of UL subframesin the allowed UL/DL reconfiguration range. The first reference UL/DLconfiguration may or may not be the same as a default UL/DLconfiguration.

The PUSCH scheduling and PUSCH HARQ-ACK timing of an eIMTA cell mayfollow a second reference UL/DL configuration with a number (e.g.,maximum number) of UL subframes in the allowed UL/DL reconfigurationrange. The second reference UL/DL configuration may or may not be thesame as a default UL/DL configuration. For subframes with allowed UL/DLswitching (e.g., subframes in one or more convertible regions), systemsand methods are provided herein for providing PDSCH HARQ-ACK timing wheneIMTA is configured.

A UL/DL reconfiguration may be needed in several cases. For example, aUL/DL reconfiguration may be needed if the allocated UL resource cannotsupport the UL traffic load. In another example, UL/DL reconfigurationmay be needed if the allocated DL resource cannot support the DL trafficload. Furthermore, a UL/DL reconfiguration may be used to adapt to atraffic load with a better matching UL/DL allocation. For instance, aUL/DL reconfiguration may be needed if a current UL/DL configurationdoes not match the UL-to-DL traffic ratio.

Various examples of the systems and methods disclosed herein are nowdescribed with reference to the figures, where like reference numbersmay indicate functionally similar elements. The systems and methods asgenerally described and illustrated in the figures herein could bearranged and designed in a wide variety of different implementations.Thus, the following more detailed description of severalimplementations, as represented in the figures, is not intended to limitscope, as claimed, but is merely representative of the systems andmethods.

FIG. 1 is a block diagram illustrating one configuration of one or moreeNBs 160 and one or more UEs 102 in which systems and methods forfeedback reporting may be implemented. The one or more UEs 102communicate with one or more eNBs 160 using one or more antennas 122a-n. For example, a UE 102 transmits electromagnetic signals to the eNB160 and receives electromagnetic signals from the eNB 160 using the oneor more antennas 122 a-n. The eNB 160 communicates with the UE 102 usingone or more antennas 180 a-n.

It should be noted that in some configurations, one or more of the UEs102 described herein may be implemented in a single device. For example,multiple UEs 102 may be combined into a single device in someimplementations. Additionally or alternatively, in some configurations,one or more of the eNBs 160 described herein may be implemented in asingle device. For example, multiple eNBs 160 may be combined into asingle device in some implementations. In the context of FIG. 1, forinstance, a single device may include one or more UEs 102 in accordancewith the systems and methods described herein. Additionally oralternatively, one or more eNBs 160 in accordance with the systems andmethods described herein may be implemented as a single device ormultiple devices.

The UE 102 and the eNB 160 may use one or more channels 119, 121 tocommunicate with each other. For example, a UE 102 may transmitinformation or data to the eNB 160 using one or more uplink channels 121and signals. Examples of uplink channels 121 include a physical uplinkcontrol channel (PUCCH) and a physical uplink shared channel (PUSCH),etc. Examples of uplink signals include a demodulation reference signal(DMRS) and a sounding reference signal (SRS), etc. The one or more eNBs160 may also transmit information or data to the one or more UEs 102using one or more downlink channels 119 and signals, for instance.Examples of downlink channels 119 include a PDCCH, an EPDCCH, a PDSCH,etc. Examples of downlink signals include a primary synchronizationsignal (PSS), a cell-specific reference signal (CRS), and a channelstate information (CSI) reference signal (CSI-RS), etc. Other kinds ofchannels or signals may be used.

Each of the one or more UEs 102 may include one or more transceivers118, one or more demodulators 114, one or more decoders 108, one or moreencoders 150, one or more modulators 154, one or more data buffers 104and one or more UE operations modules 124. For example, one or morereception and/or transmission paths may be implemented in the UE 102.For convenience, only a single transceiver 118, decoder 108, demodulator114, encoder 150 and modulator 154 are illustrated in the UE 102, thoughmultiple parallel elements (e.g., transceivers 118, decoders 108,demodulators 114, encoders 150 and modulators 154) may be implemented.

The transceiver 118 may include one or more receivers 120 and one ormore transmitters 158. The one or more receivers 120 may receive signalsfrom the eNB 160 using one or more antennas 122 a-n. For example, thereceiver 120 may receive and downconvert signals to produce one or morereceived signals 116. The one or more received signals 116 may beprovided to a demodulator 114. The one or more transmitters 158 maytransmit signals to the eNB 160 using one or more antennas 122 a-n. Forexample, the one or more transmitters 158 may upconvert and transmit oneor more modulated signals 156.

The demodulator 114 may demodulate the one or more received signals 116to produce one or more demodulated signals 112. The one or moredemodulated signals 112 may be provided to the decoder 108. The UE 102may use the decoder 108 to decode signals. The decoder 108 may produceone or more decoded signals 106, 110. For example, a first UE-decodedsignal 106 may comprise received payload data, which may be stored in adata buffer 104. A second UE-decoded signal 110 may comprise overheaddata and/or control data. For example, the second UE-decoded signal 110may provide data that may be used by the UE operations module 124 toperform one or more operations.

As used herein, the term “module” may mean that a particular element orcomponent may be implemented in hardware, software or a combination ofhardware and software. However, it should be noted that any elementdenoted as a “module” herein may alternatively be implemented inhardware. For example, the UE operations module 124 may be implementedin hardware, software or a combination of both.

In general, the UE operations module 124 may enable the UE 102 tocommunicate with the one or more eNBs 160. The UE operations module 124may include one or more of a UL/DL reconfiguration DCI decoder 128, a UEPUCCH resource module 130 and a UE PDSCH HARQ-ACK module 132.

The UL/DL reconfiguration DCI decoder 128 may decode a UL/DLreconfiguration DCI with an eIMTA-RNTI on a PDCCH/EPDCCH. The UL/DLreconfiguration DCI with an eIMTA-RNTI may be received from an eNB 160.Explicit reconfiguration signaling (e.g., the reconfiguration DCI) maybe used to indicate the actual TDD UL/DL configuration. In oneimplementation, the eIMTA-RNTI may be UE-specifically configured viaRRC. Different UEs 102 may be configured with different eIMTA-RNTIs.

In some implementations, an eIMTA TDD cell may support dynamic UL/DLreconfiguration with traffic adaptation. In eIMTA, the PDSCH HARQ-ACKtiming may be based on an RRC-configured DL HARQ referenceconfiguration. In fallback mode operation, a UE 102 only monitors the DLand special subframes defined by the system information block type 1(SIB1) UL/DL configuration. Thus, to avoid ambiguity with the eNB 160,the HARQ-ACK reporting of the monitored subframes may be specified.

Furthermore, if a UE 102 is configured with PUCCH format 3, then the UE102 may follow a HARQ-ACK fallback operation using PUCCH format 3. Butif there is only a semi-persistent scheduling (SPS) transmission, oronly one DL subframe detected with a Downlink Assignment Index (DAI)value of 1 in a DL assignment on a cell, the UE 102 may report theHARQ-ACK with PUCCH format 1a/1b instead of PUCCH format 3. As usedherein, “DAT” may also be referred to as downlink DAI (DL DAI).

In an eIMTA TDD cell, a UE 102 may be configured with a DL HARQreference UL/DL configuration by RRC signaling. The PDSCH HARQ-ACKtiming may be performed based on the DL HARQ reference UL/DLconfiguration. Thus, the DL association set according to the DL HARQreference configuration defines the potential subframes that can carry aPDSCH for the UE 102. On the other hand, some of the subframes in the DLassociation set may be configured as UL by reconfiguration DCI, whichindicate the UL/DL configuration used in a reconfiguration period.

According to the systems and methods described herein, the detection ofreconfiguration signaling may be implicitly reported to the eNB 160 byPUCCH channel selection. This may minimize the HARQ-ACK payload.

If a UE 102 is configured with PUCCH format 3, under fallback operationwhen valid UL/DL configuration in the reconfiguration Downlink ControlInformation (DCI) is not detected, the actual DL and special subframeallocation is unknown to the UE 102, and the UE 102 monitors only the DLand special subframes specified by the SIB1 configuration. As usedherein, “SIB1 configuration” refers to the UL/DL configuration in theSystemInformationBlockType1 or RadioResourceConfigCommon signaling inthe case that the eIMTA cell is a PCell and theRadioResourceConfigCommonSCell-r10 in the case that the eIMTA cell is anSCell. However, since some subframes are not monitored, there may bemismatch on the DAI values.

The UL/DL reconfiguration DCI decoder 128 may determine if one or morevalid UL/DL configurations in the UL/DL reconfiguration DCI witheIMTA-RNTI for all configured eIMTA cells are received. The status ofthe reconfiguration DCI with eIMTA-RNTI may be based on whether a validUL/DL configuration in the reconfiguration DCI with eIMTA-RNTI for agiven reconfiguration period is detected (e.g., received) or not.

If there is more than one eIMTA cell configured, for the PUCCH reportingin a given uplink subframe, valid UL/DL configurations in thereconfiguration DCI with eIMTA-RNTI are considered as detected if validUL/DL configurations in the reconfiguration DCI signals for all eIMTAcells are correctly received (e.g., detected) based on the DLassociation set of the uplink of each eIMTA cell. Furthermore, validUL/DL configurations in the reconfiguration DCI with eIMTA-RNTI areconsidered as not detected if a valid UL/DL configuration in thereconfiguration DCI signal of any eIMTA cell is not received (e.g.,detected) based on the DL association set of the uplink of the eIMTAcell.

The UE PUCCH resource module 130 may determine a PUCCH resource forPDSCH HARQ-ACK reporting based on whether valid UL/DL configurations inthe UL/DL reconfiguration DCI with eIMTA-RNTI for all of the configuredeIMTA cells corresponding to a subframe for the PUCCH resource arereceived. If a UE 102 is configured with PUCCH format 3, under normaloperation when valid UL/DL configuration in the reconfiguration DCI isdetected (e.g., DCI is received), the DL and special subframes accordingto the UL/DL configuration in the reconfiguration DCI may be used forHARQ-ACK reports to minimize the HARQ-ACK bits on a PUCCH or PUSCHfeedback.

The PUCCH format 3 resource may be configured by higher layer signalingand may be indicated by the Transmitter Power Control (TPC) field if thePDSCH is scheduled by a PDCCH on a PCell or an PDCCH/EPDCCH on a SCell.The PUCCH format 3 resource may be configured by higher layer signalingand indicated by the HARQ-ACK resource offset (e.g., acknowledgmentresource offset (ARO)) bits if the PDSCH is scheduled by an EPDCCH onthe PCell. This may be accomplished as described in connection with FIG.7.

If valid UL/DL configurations in the UL/DL reconfiguration DCI witheIMTA-RNTI of all configured eIMTA cells corresponding to a subframe forthe PUCCH resource are detected, then the UE PUCCH resource module 130may select the PUCCH resource based on at least one of a TransmitterPower Control (TPC) field (e.g., an acknowledgment resource indicator(ARI)) or an acknowledgment resource offset (ARO) in a DL schedulingDCI. The Transmitter Power Control (TPC) field may be included in a DLgrant.

In one case, if a PDSCH is detected on an SCell in a DL assignment byPDCCH/EPDCCH, or a DAI value is greater than 1 in a detected PDCCH on aPCell, then the UE PUCCH resource module 130 may determine a PUCCHformat 3 resource based on the TPC field in a PDCCH/EPDCCH assignmentwith a DAI value greater than 1. In another case, if there is no PDSCHdetected on an SCell and a DAI value is greater than 1 in a detectedEPDCCH on a PCell, then the UE PUCCH resource module 130 may determine aPUCCH format 3 resource based on a HARQ-ACK resource offset field in aDCI format of a corresponding EPDCCH assignment with a DAI value greaterthan 1.

In yet another case, if there is only one PDSCH detected with a DAIvalue of 1, excluding SPS on a PCell, then the UE PUCCH resource module130 may determine a PUCCH format 1a/1b resource based on the number ofcontrol channel elements (CCEs). In this case, a HARQ-ACK fallback modemay be used if there is only one PDSCH with a DAI value of 1 in a DLassignment is detected on the PCell. The UE PUCCH resource module 130may follow the number of CCEs.

If at least one valid UL/DL configuration in the UL/DL reconfigurationDCI with eIMTA-RNTI for at least one configured eIMTA cell correspondingto a subframe for the PUCCH resource is not received, then the UE PUCCHresource module 130 may select the PUCCH resource based on at least oneof a predefined offset or a separate PUCCH resource. To indicate themisdetection of reconfiguration DCI, a different PUCCH resource can beused for the HARQ-ACK reporting. The PUCCH resource can be determined bythe PUCCH resource for normal operation with an extra offset value. Theoffset value can be fixed or predefined (e.g., 1). The offset value canbe signaled by higher layer (e.g., RRC configuration).

In one case, if a PDSCH is detected on an SCell in a DL assignment byPDCCH/EPDCCH, or a DAI value is greater than 1 in a detected PDCCH on aPCell, then the UE PUCCH resource module 130 may determine a PUCCHformat 3 resource based on a predefined offset or a separate PUCCHresource and a TPC field in a PDCCH/EPDCCH assignment with a DAI valuegreater than 1. In another case, if there is no PDSCH detected on anSCell and a DAI value is greater than 1 in a detected EPDCCH on a PCell,then the UE PUCCH resource module 130 may determine a PUCCH format 3resource based on at least one of a predefined offset or a separatePUCCH resource and a HARQ-ACK resource offset field in a DCI format of acorresponding EPDCCH assignment with a DAI value greater than 1.

In yet another case, if only one PDSCH with a DAI equal to 1 is detectedon the PCell, the HARQ-ACK reporting may be performed on PUCCH format1a/1b, instead of PUCCH format 3 with an extra offset value. In oneimplementation, if there is only one PDSCH detected with a DAI value of1, excluding SPS on a PCell, then the UE PUCCH resource module 130 maydetermine a PUCCH format 1a/1b resource based on the number of CCEs.

The UE PDSCH HARQ-ACK module 132 may send PDSCH HARQ-ACK information onthe selected PUCCH resource in an uplink subframe. The PDSCH HARQ-ACKinformation may be determined in different ways. In one case, if PUCCHformat 3 is configured and valid UL/DL configurations in the UL/DLreconfiguration DCI with eIMTA-RNTI for all of the configured eIMTAcells corresponding to a subframe for the PUCCH resource are received,then the UE PDSCH HARQ-ACK module 132 may determine the PDSCH HARQ-ACKinformation based on at least one of a DL subframe and a specialsubframe according to the UL/DL configuration in the UL/DLreconfiguration DCI in a DL association set for a given UL subframe ofeach configured eIMTA cell.

However, if PUCCH format 3 is configured and one or more valid UL/DLconfigurations in the UL/DL reconfiguration DCI with eIMTA-RNTI for atleast one of the one or more configured eIMTA cells corresponding to asubframe for the PUCCH resource is not received, the UE PDSCH HARQ-ACKmodule 132 may report only the HARQ-ACK bits of the fixed DL and specialsubframes specified by the SIB1 configuration on PUCCH format 3.Therefore, the UE PDSCH HARQ-ACK module 132 may determine the PDSCHHARQ-ACK information based on at least one of a DL subframe and aspecial subframe according to a system information block type 1 (SIB1)configuration in a DL association set according to a DL HARQ referenceconfiguration for a given UL subframe of each configured eIMTA cell.When a configured eIMTA cell is a PCell, the SIB1 configuration mayinclude a UL/DL configuration in the SIB1 signaling orRadioResourceConfigCommon signaling. When a configured eIMTA cell is anSCell, the SIB1 configuration may include a UL/DL configuration inRadioResourceConfigCommonSCell-r10 signaling.

In another alternative, the UE PDSCH HARQ-ACK module 132 may report theHARQ-ACK bits based on the DL and special subframes specified by the DLHARQ reference configuration on PUCCH format 3. Therefore, if PUCCHformat 3 is configured and a valid UL/DL configuration in the UL/DLreconfiguration DCI with eIMTA-RNTI for at least one configured eIMTAcell corresponding to a subframe for the PUCCH resource is not received,then the UE PDSCH HARQ-ACK module 132 may determine the PDSCH HARQ-ACKinformation based on a DL association set according to a DL HARQreference configuration for a given UL subframe of each configured eIMTAcell.

The UE operations module 124 may provide information 148 to the one ormore receivers 120. For example, the UE operations module 124 may informthe receiver(s) 120 when to receive retransmissions.

The UE operations module 124 may provide information 138 to thedemodulator 114. For example, the UE operations module 124 may informthe demodulator 114 of a modulation pattern anticipated fortransmissions from the eNB 160.

The UE operations module 124 may provide information 136 to the decoder108. For example, the UE operations module 124 may inform the decoder108 of an anticipated encoding for transmissions from the eNB 160.

The UE operations module 124 may provide information 142 to the encoder150. The information 142 may include data to be encoded and/orinstructions for encoding. For example, the UE operations module 124 mayinstruct the encoder 150 to encode transmission data 146 and/or otherinformation 142. The other information 142 may include the PDSCHHARQ-ACK information.

The encoder 150 may encode transmission data 146 and/or otherinformation 142 provided by the UE operations module 124. For example,encoding the data 146 and/or other information 142 may involve errordetection and/or correction coding, mapping data to space, time and/orfrequency resources for transmission, multiplexing, etc. The encoder 150may provide encoded data 152 to the modulator 154.

The UE operations module 124 may provide information 144 to themodulator 154. For example, the UE operations module 124 may inform themodulator 154 of a modulation type (e.g., constellation mapping) to beused for transmissions to the eNB 160. The modulator 154 may modulatethe encoded data 152 to provide one or more modulated signals 156 to theone or more transmitters 158.

The UE operations module 124 may provide information 140 to the one ormore transmitters 158. This information 140 may include instructions forthe one or more transmitters 158. For example, the UE operations module124 may instruct the one or more transmitters 158 when to transmit asignal to the eNB 160. In some configurations, this may be based on theUL/DL reconfiguration DCI. For instance, the one or more transmitters158 may transmit during a UL subframe. The one or more transmitters 158may upconvert and transmit the modulated signal(s) 156 to one or moreeNBs 160.

The eNB 160 may include one or more transceivers 176, one or moredemodulators 172, one or more decoders 166, one or more encoders 109,one or more modulators 113, one or more data buffers 162 and one or moreeNB operations modules 182. For example, one or more reception and/ortransmission paths may be implemented in an eNB 160. For convenience,only a single transceiver 176, decoder 166, demodulator 172, encoder 109and modulator 113 are illustrated in the eNB 160, though multipleparallel elements (e.g., transceivers 176, decoders 166, demodulators172, encoders 109 and modulators 113) may be implemented.

The transceiver 176 may include one or more receivers 178 and one ormore transmitters 117. The one or more receivers 178 may receive signalsfrom the UE 102 using one or more antennas 180 a-n. For example, thereceiver 178 may receive and downconvert signals to produce one or morereceived signals 174. The one or more received signals 174 may beprovided to a demodulator 172. The one or more transmitters 117 maytransmit signals to the UE 102 using one or more antennas 180 a-n. Forexample, the one or more transmitters 117 may upconvert and transmit oneor more modulated signals 115.

The demodulator 172 may demodulate the one or more received signals 174to produce one or more demodulated signals 170. The one or moredemodulated signals 170 may be provided to the decoder 166. The eNB 160may use the decoder 166 to decode signals. The decoder 166 may produceone or more decoded signals 164, 168. For example, a first eNB-decodedsignal 164 may comprise received payload data, which may be stored in adata buffer 162. A second eNB-decoded signal 168 may comprise overheaddata and/or control data. For example, the second eNB-decoded signal 168may provide data (e.g., PDSCH HARQ-ACK information) that may be used bythe eNB operations module 182 to perform one or more operations.

In general, the eNB operations module 182 may enable the eNB 160 tocommunicate with the one or more UEs 102. The eNB operations module 182may include one or more of a UL/DL reconfiguration DCI encoder 196, aneNB PUCCH resource module 198 and an eNB PDSCH HARQ-ACK module 107.

The UL/DL reconfiguration DCI encoder 196 may encode and transmit aUL/DL reconfiguration DCI with an eIMTA-RNTI on a PDCCH/EPDCCH. TheUL/DL reconfiguration DCI with an eIMTA-RNTI may be sent to a UE 102.Explicit reconfiguration signaling (e.g., the reconfiguration DCI) maybe used to indicate the actual TDD UL/DL configuration. The eIMTA-RNTImay be UE-specifically configured via RRC. Different UEs 102 may beconfigured with different eIMTA-RNTIs.

The eNB 160 may be informed of a misdetection of reconfiguration DCI bythe UE 102 through different PUCCH resources that are used for theHARQ-ACK reporting. The eNB PUCCH resource module 198 may assume thatthe UE 102 determines a PUCCH resource for PDSCH HARQ-ACK reportingbased on whether valid UL/DL configurations in the UL/DL reconfigurationDCI with eIMTA-RNTI for all of the configured eIMTA cells correspondingto a subframe for the PUCCH resource are received. If valid UL/DLconfigurations in the UL/DL reconfiguration DCI with eIMTA-RNTI of allconfigured eIMTA cells corresponding to a subframe for the PUCCHresource are detected, then the UE 102 may select the PUCCH resourcebased on at least one of a TPC field (i.e., an ARI) or an ARO in a DLscheduling DCI.

In one case, if the UE 102 detects a PDSCH on an SCell in a DLassignment by PDCCH/EPDCCH, or a DAI value is greater than 1 in adetected PDCCH on a PCell, then the eNB PUCCH resource module 198 mayassume that the UE 102 determines a PUCCH format 3 resource based on aTPC field in a PDCCH/EPDCCH assignment with a DAI value greater than 1.In another case, if the UE 102 does not detect a PDSCH on an SCell and aDAI value is greater than 1 in a detected EPDCCH on a PCell, then theeNB PUCCH resource module 198 may assume that the UE 102 determines aPUCCH format 3 resource based on a HARQ-ACK resource offset field in aDCI format of a corresponding EPDCCH assignment with a DAI value greaterthan 1.

In yet another case, if the UE 102 detects only one PDSCH with a DAIvalue of 1, excluding SPS on a PCell, then the eNB PUCCH resource module198 may assume that the UE 102 determines a PUCCH format 1a/1b resourcebased on the number of CCEs.

If the UE 102 does not receive at least one valid UL/DL configuration inthe UL/DL reconfiguration DCI with eIMTA-RNTI for at least oneconfigured eIMTA cell corresponding to a subframe for the PUCCHresource, then the eNB PUCCH resource module 198 may assume that the UE102 selects the PUCCH resource based on at least one of a predefinedoffset or a separate PUCCH resource. During fallback operation, thePUCCH resource can be determined based on an extra offset value. Theoffset value can be fixed or predefined (e.g., 1). The offset value canbe signaled by higher layer signaling (e.g., RRC configuration).

In one case, if the UE 102 detects a PDSCH on an SCell in a DLassignment by PDCCH/EPDCCH, or a DAI value is greater than 1 in adetected PDCCH on a PCell, then the eNB PUCCH resource module 198 mayassume that the UE 102 determines a PUCCH format 3 resource based on apredefined offset or a separate PUCCH resource and a TPC field in aPDCCH/EPDCCH assignment with a DAI value greater than 1. In anothercase, if the UE 102 does not detect a PDSCH on an SCell and a DAI valueis greater than 1 in a detected EPDCCH on a PCell, then the eNB PUCCHresource module 198 may assume that the UE 102 determines a PUCCH format3 resource based on at least one of a predefined offset or a separatePUCCH resource and a HARQ-ACK resource offset field in a DCI format of acorresponding EPDCCH assignment with a DAI value greater than 1.

In yet another case, if the UE 102 detects only one PDSCH with a DAIequal to 1 on the PCell, the HARQ-ACK reporting may be performed onPUCCH format 1a/1b, instead of PUCCH format 3 with an extra offsetvalue.

The eNB PDSCH HARQ-ACK module 107 may receive PDSCH HARQ-ACK informationon the selected PUCCH resource in an uplink subframe. The PDSCH HARQ-ACKinformation may be determined in different ways. In one case, if PUCCHformat 3 is configured and valid UL/DL configurations in the UL/DLreconfiguration DCI with eIMTA-RNTI for all of the configured eIMTAcells corresponding to a subframe for the PUCCH resource are received bythe UE 102, then the eNB PDSCH HARQ-ACK module 107 may assume that theUE 102 determines the PDSCH HARQ-ACK information based on at least oneof a DL subframe and a special subframe according to the UL/DLconfiguration in the UL/DL reconfiguration DCI in a DL association setfor a given UL subframe of each configured eIMTA cell.

However, if PUCCH format 3 is configured and one or more valid UL/DLconfigurations in the UL/DL reconfiguration DCI with eIMTA-RNTI for atleast one of the one or more configured eIMTA cells corresponding to asubframe for the PUCCH resource is not received by the UE 102, the eNBPDSCH HARQ-ACK module 107 may assume that the UE 102 determines thePDSCH HARQ-ACK information based on at least one of a DL subframe and aspecial subframe according to an SIB1 configuration in a DL associationset according to a DL HARQ reference configuration for a given ULsubframe of each configured eIMTA cell.

In another alternative, if PUCCH format 3 is configured and a validUL/DL configuration in the UL/DL reconfiguration DCI with eIMTA-RNTI forat least one configured eIMTA cell corresponding to a subframe for thePUCCH resource is not received by the UE 102, then the eNB PDSCHHARQ-ACK module 107 may assume that the UE 102 determines the PDSCHHARQ-ACK information based on a DL association set according to a DLHARQ reference configuration for a given UL subframe of each configuredeIMTA cell.

The eNB operations module 182 may provide information 190 to the one ormore receivers 178. For example, the eNB operations module 182 mayinform the receiver(s) 178 when or when not to receive transmissionsfrom the UE(s) 102.

The eNB operations module 182 may provide information 188 to thedemodulator 172. For example, the eNB operations module 182 may informthe demodulator 172 of a modulation pattern anticipated fortransmissions from the UE(s) 102.

The eNB operations module 182 may provide information 186 to the decoder166. For example, the eNB operations module 182 may inform the decoder166 of an anticipated encoding for transmissions from the UE(s) 102.

The eNB operations module 182 may provide information 101 to the encoder109. The information 101 may include data to be encoded and/orinstructions for encoding. For example, the eNB operations module 182may instruct the encoder 109 to encode transmission data 105 and/orother information 101.

The encoder 109 may encode transmission data 105 and/or otherinformation 101 provided by the eNB operations module 182. For example,encoding the data 105 and/or other information 101 may involve errordetection and/or correction coding, mapping data to space, time and/orfrequency resources for transmission, multiplexing, etc. The encoder 109may provide encoded data 111 to the modulator 113. The transmission data105 may include network data to be relayed to the UE 102.

The eNB operations module 182 may provide information 103 to themodulator 113. This information 103 may include instructions for themodulator 113. For example, the eNB operations module 182 may inform themodulator 113 of a modulation type (e.g., constellation mapping) to beused for transmissions to the UE(s) 102. The modulator 113 may modulatethe encoded data 111 to provide one or more modulated signals 115 to theone or more transmitters 117.

The eNB operations module 182 may provide information 192 to the one ormore transmitters 117. This information 192 may include instructions forthe one or more transmitters 117. For example, the eNB operations module182 may instruct the one or more transmitters 117 when to (or when notto) transmit a signal to the UE(s) 102. In some implementations, thismay be based on the UL/DL reconfiguration DCI. The one or moretransmitters 117 may upconvert and transmit the modulated signal(s) 115to one or more UEs 102.

It should be noted that a DL subframe may be transmitted from the eNB160 to one or more UEs 102 and that a UL subframe may be transmittedfrom one or more UEs 102 to the eNB 160. Furthermore, both the eNB 160and the one or more UEs 102 may transmit data in a standard specialsubframe.

It should also be noted that one or more of the elements or partsthereof included in the eNB(s) 160 and UE(s) 102 may be implemented inhardware. For example, one or more of these elements or parts thereofmay be implemented as a chip, circuitry or hardware components, etc. Itshould also be noted that one or more of the functions or methodsdescribed herein may be implemented in and/or performed using hardware.For example, one or more of the methods described herein may beimplemented in and/or realized using a chipset, an application-specificintegrated circuit (ASIC), a large-scale integrated (LSI) circuit orintegrated circuit, etc.

FIG. 2 is a flow diagram illustrating one implementation of a method 200for feedback reporting by a UE 102. The UE 102 may be configured witheIMTA support. The UE 102 may decode 202 a UL/DL reconfiguration DCIwith an eIMTA-RNTI on a PDCCH/EPDCCH. The UL/DL reconfiguration DCI withan eIMTA-RNTI may be received from an eNB 160. Explicit reconfigurationsignaling (e.g., the reconfiguration DCI) may be used to indicate theactual TDD UL/DL configuration. The eIMTA-RNTI may be UE-specificallyconfigured via RRC. Different UEs 102 may be configured with differenteIMTA-RNTIs.

The UE 102 may determine 204 if one or more valid UL/DL configurationsin the UL/DL reconfiguration DCI with eIMTA-RNTI for all configuredeIMTA cells are received. The status of the reconfiguration DCI witheIMTA-RNTI may be based on whether a valid UL/DL configuration in thereconfiguration DCI with eIMTA-RNTI for a given reconfiguration periodis detected (e.g., received) or not.

If there is more than one eIMTA cell configured, for the PUCCH reportingin a given uplink subframe, valid UL/DL configurations in thereconfiguration DCI with eIMTA-RNTI are considered as detected if validUL/DL configurations in the reconfiguration DCI signals for all eIMTAcells are correctly received (e.g., detected) based on the DLassociation set of the uplink of each eIMTA cell. Furthermore, validUL/DL configurations in the reconfiguration DCI with eIMTA-RNTI areconsidered as not detected if a valid UL/DL configuration in thereconfiguration DCI signal of any eIMTA cell is not received (e.g.,detected) based on the DL association set of the uplink of the eIMTAcell.

The UE 102 may determine 206 if PUCCH format 3 is configured. The PUCCHformat 3 resource may be configured by higher layer signaling and may beindicated by the TPC field if the PDSCH is scheduled by a PDCCH on aPCell or an PDCCH/EPDCCH on a SCell. The PUCCH format 3 resource may beconfigured by higher layer signaling and indicated by the HARQ-ACKresource offset (e.g., ARO) bits if the PDSCH is scheduled by an EPDCCHon the PCell. This may be accomplished as described in connection withFIG. 7.

The UE 102 may determine 208 a PUCCH resource for PDSCH HARQ-ACKreporting based on whether valid UL/DL configurations in the UL/DLreconfiguration DCI with eIMTA-RNTI for all of the configured eIMTAcells corresponding to a subframe for the PUCCH resource are received.If a UE 102 is configured with PUCCH format 3, under normal operationwhen valid UL/DL configuration in the reconfiguration DCI is detected(e.g., DCI is received), the DL and special subframes according to theUL/DL configuration in the reconfiguration DCI should be used forHARQ-ACK reports to minimize the HARQ-ACK bits on a PUCCH or PUSCHfeedback.

If valid UL/DL configurations in the UL/DL reconfiguration DCI witheIMTA-RNTI of all configured eIMTA cells corresponding to a subframe forthe PUCCH resource are detected, then the UE 102 may select the PUCCHresource based on at least one of a TPC field (i.e., an ARI) or an AROin a DL scheduling DCI.

In one case, if a PDSCH is detected on an SCell in a DL assignment byPDCCH/EPDCCH, or a DAI value is greater than 1 in a detected PDCCH on aPCell, then the UE 102 may determine 208 a PUCCH format 3 resource basedon a TPC field in a PDCCH/EPDCCH assignment with a DAI value greaterthan 1. In another case, if there is no PDSCH detected on an SCell and aDAI value is greater than 1 in a detected EPDCCH on a PCell, then the UE102 may determine 208 a PUCCH format 3 resource based on a HARQ-ACKresource offset field in a DCI format of a corresponding EPDCCHassignment with a DAI value greater than 1.

In yet another case, if there is only one PDSCH detected with a DAIvalue of 1, excluding SPS on a PCell, then the UE 102 may determine 208a PUCCH format 1a/1b resource based on the number of CCEs. In this case,a HARQ-ACK fallback mode may be used if there is only one PDSCH with aDAI value of 1 in a DL assignment that is detected on the PCell. The UE102 may follow the number of CCEs.

If the UE 102 determines 204 that at least one valid UL/DL configurationin the UL/DL reconfiguration DCI with eIMTA-RNTI for at least oneconfigured eIMTA cell corresponding to a subframe for the PUCCH resourceis not received, then the UE 102 may select the PUCCH resource based onat least one of a predefined offset or a separate PUCCH resource. Toindicate the misdetection of reconfiguration DCI, a different PUCCHresource can be used for the HARQ-ACK reporting. The PUCCH resource canbe determined by the PUCCH resource for normal operation with an extraoffset value. The offset value can be fixed or predefined (e.g., 1). Theoffset value can be signaled by higher layer (e.g., RRC configuration).

In one case, if a PDSCH is detected on an SCell in a DL assignment byPDCCH/EPDCCH, or a DAI value is greater than 1 in a detected PDCCH on aPCell, then the UE 102 may determine 208 a PUCCH format 3 resource basedon a predefined offset or a separate PUCCH resource and a TPC field in aPDCCH/EPDCCH assignment with a DAI value greater than 1. In anothercase, if there is no PDSCH detected on an SCell and a DAI value isgreater than 1 in a detected EPDCCH on a PCell, then the UE 102 maydetermine 208 a PUCCH format 3 resource based on at least one of apredefined offset or a separate PUCCH resource and a HARQ-ACK resourceoffset field in a DCI format of a corresponding EPDCCH assignment with aDAI value greater than 1.

In yet another case, if only one PDSCH with a DAI equal to 1 is detectedon the PCell, the HARQ-ACK reporting may be performed on PUCCH format1a/1b, instead of PUCCH format 3 with an extra offset value. In oneimplementation, if there is only one PDSCH detected with a DAI value of1, excluding SPS on a PCell, then the UE 102 may determine 208 a PUCCHformat 1a/1b resource based on the number of CCEs.

The UE 102 may send 210 PDSCH HARQ-ACK information on the selected PUCCHresource in an uplink subframe. In one case, if PUCCH format 3 isconfigured and valid UL/DL configurations in the UL/DL reconfigurationDCI with eIMTA-RNTI for all of the configured eIMTA cells correspondingto a subframe for the PUCCH resource are received, then the UE 102 maydetermine the PDSCH HARQ-ACK information based on at least one of a DLsubframe and a special subframe according to the UL/DL configuration inthe UL/DL reconfiguration DCI in a DL association set for a given ULsubframe of each configured eIMTA cell.

However, if PUCCH format 3 is configured and one or more valid UL/DLconfigurations in the UL/DL reconfiguration DCI with eIMTA-RNTI for atleast one of the one or more configured eIMTA cells corresponding to asubframe for the PUCCH resource is not received, the UE 102 may reportonly the HARQ-ACK bits of the fixed DL and special subframes specifiedby the SIB1 configuration on PUCCH format 3. Therefore, the UE 102 maydetermine the PDSCH HARQ-ACK information based on at least one of a DLsubframe and a special subframe according to an SIB1 configuration in aDL association set according to a DL HARQ reference configuration for agiven UL subframe of each configured eIMTA cell. When a configured eIMTAcell is a PCell, the SIB1 configuration may include a UL/DLconfiguration in the SIB1 signaling or RadioResourceConfigCommonsignaling. When a configured eIMTA cell is an SCell, the SIB1configuration may include a UL/DL configuration inRadioResourceConfigCommonSCell-r10 signaling.

In another alternative, the UE 102 may report the HARQ-ACK bits based onthe DL and special subframes specified by the DL HARQ referenceconfiguration on PUCCH format 3. Therefore, if PUCCH format 3 isconfigured and a valid UL/DL configuration in the UL/DL reconfigurationDCI with eIMTA-RNTI for at least one configured eIMTA cell correspondingto a subframe for the PUCCH resource is not received, then the UE 102may determine the PDSCH HARQ-ACK information based on a DL associationset according to a DL HARQ reference configuration for a given ULsubframe of each configured eIMTA cell.

FIG. 3 is a flow diagram illustrating one implementation of a method 300for feedback reporting by an eNB 160. The eNB 160 may be configured witheIMTA support. The eNB 160 may transmit 302 a UL/DL reconfiguration DCIwith an eIMTA-RNTI on a PDCCH/EPDCCH. The UL/DL reconfiguration DCI withan eIMTA-RNTI may be sent to a UE 102. Explicit reconfigurationsignaling (e.g., the reconfiguration DCI) may be used to indicate theactual TDD UL/DL configuration. The eIMTA-RNTI may be UE-specificallyconfigured via RRC. Different UEs 102 may be configured with differenteIMTA-RNTIs.

According to the systems and methods described herein, the detection ofreconfiguration signaling may be implicitly reported to the eNB 160 byPUCCH channel selection. This may minimize the HARQ-ACK payload in allcases.

The eNB 160 may assume 304 that the UE 102 determines if one or morevalid UL/DL configurations in the UL/DL reconfiguration DCI witheIMTA-RNTI for all configured eIMTA cells are received. The status ofthe reconfiguration DCI with eIMTA-RNTI may be based on whether a validUL/DL configuration in the reconfiguration DCI with eIMTA-RNTI for agiven reconfiguration period is detected (e.g., received) or not.

The eNB 160 may assume 306 that the UE 102 determines if physical uplinkcontrol channel (PUCCH) format 3 is configured. This may be accomplishedas described in connection with FIG. 7.

The eNB 160 may assume 308 that the UE 102 determines a PUCCH resourcefor PDSCH HARQ-ACK reporting based on whether valid UL/DL configurationsin the UL/DL reconfiguration DCI with eIMTA-RNTI for all of theconfigured eIMTA cells corresponding to a subframe for the PUCCHresource are received. If valid UL/DL configurations in the UL/DLreconfiguration DCI with eIMTA-RNTI of all configured eIMTA cellscorresponding to a subframe for the PUCCH resource are detected, thenthe UE 102 may select the PUCCH resource based on at least one of a TPCfield (i.e., an ARI) or an ARO in a DL scheduling DCI.

In one case, if the UE 102 detects a PDSCH on an SCell in a DLassignment by PDCCH/EPDCCH, or a DAI value is greater than 1 in adetected PDCCH on a PCell, then the eNB 160 may assume 308 that the UE102 determines a PUCCH format 3 resource based on a transmitter powercontrol (TPC) field in a PDCCH/EPDCCH assignment with a DAI valuegreater than 1. In another case, if the UE 102 does not detect a PDSCHon an SCell and a DAI value is greater than 1 in a detected EPDCCH on aPCell, then the eNB 160 may assume 308 that the UE 102 determines aPUCCH format 3 resource based on a HARQ-ACK resource offset field in aDCI format of a corresponding EPDCCH assignment with a DAI value greaterthan 1.

In yet another case, if the UE 102 detects only one PDSCH with a DAIvalue of 1, excluding SPS on a PCell, then the eNB 160 may assume 308that the UE 102 determines a PUCCH format 1a/1b resource based on thenumber of CCEs.

If the UE 102 does not receive at least one valid UL/DL configuration inthe UL/DL reconfiguration DCI with eIMTA-RNTI for at least oneconfigured eIMTA cell corresponding to a subframe for the PUCCHresource, then the eNB 160 may assume 308 that the UE 102 selects thePUCCH resource based on at least one of a predefined offset or aseparate PUCCH resource. The eNB 160 may be informed of a misdetectionof reconfiguration DCI by the UE 102 through different PUCCH resourcesthat may be used for the HARQ-ACK reporting. During fallback operation,the PUCCH resource can be determined based on an extra offset value. Theoffset value can be fixed or predefined (e.g., 1). The offset value canbe signaled by higher layer (e.g., RRC configuration).

In one case, if the UE 102 detects a PDSCH on an SCell in a DLassignment by PDCCH/EPDCCH, or a DAI value is greater than 1 in adetected PDCCH on a PCell, then the eNB 160 may assume 308 that the UE102 determines a PUCCH format 3 resource based on a predefined offset ora separate PUCCH resource and a TPC field in a PDCCH/EPDCCH assignmentwith a DAI value greater than 1. In another case, if the UE 102 does notdetect a PDSCH on an SCell and a DAI value is greater than 1 in adetected EPDCCH on a PCell, then the eNB 160 may assume 308 that the UE102 determines a PUCCH format 3 resource based on at least one of apredefined offset or a separate PUCCH resource and a HARQ-ACK resourceoffset field in a DCI format of a corresponding EPDCCH assignment with aDAI value greater than 1.

In yet another case, if the UE 102 detects only one PDSCH with a DAIequal to 1 on the PCell, the HARQ-ACK reporting may be performed onPUCCH format 1a/1b, instead of PUCCH format 3 with an extra offsetvalue.

The eNB 160 may monitor 310 potential PUCCH resources and receive PDSCHHARQ-ACK information on the detected PUCCH resource in an uplinksubframe. In some implementations, the eNB 160 may monitor all possiblePUCCH reporting cases. For example, the eNB 160 may monitor 310 thePUCCH resource when the reconfiguration is detected by the UE 102. TheeNB 160 may also monitor 310 the PUCCH resource when the reconfigurationis not detected by the UE 102. The eNB 160 may further monitor 310 thePUCCH format 1a/1b resource for a PCell DL subframe with a DAI=1 (forHARQ-ACK fallback reporting on PUCCH format 1a/1b instead of PUCCHformat 3).

In one case, if PUCCH format 3 is configured and valid UL/DLconfigurations in the UL/DL reconfiguration DCI with eIMTA-RNTI for allof the configured eIMTA cells corresponding to a subframe for the PUCCHresource are received by the UE 102, then the eNB 160 may assume thatthe UE 102 determines the PDSCH HARQ-ACK information based on at leastone of a DL subframe and a special subframe according to the UL/DLconfiguration in the UL/DL reconfiguration DCI in a DL association setfor a given UL subframe of each configured eIMTA cell.

However, if PUCCH format 3 is configured and one or more valid UL/DLconfigurations in the UL/DL reconfiguration DCI with eIMTA-RNTI for atleast one of the one or more configured eIMTA cells corresponding to asubframe for the PUCCH resource is not received by the UE 102, the eNB160 may assume that the UE 102 determines the PDSCH HARQ-ACK informationbased on at least one of a DL subframe and a special subframe accordingto an SIB1 configuration in a DL association set according to a DL HARQreference configuration for a given UL subframe of each configured eIMTAcell.

In another alternative, if PUCCH format 3 is configured and a validUL/DL configuration in the UL/DL reconfiguration DCI with eIMTA-RNTI forat least one configured eIMTA cell corresponding to a subframe for thePUCCH resource is not received by the UE 102, then the eNB 160 mayassume that the UE 102 determines the PDSCH HARQ-ACK information basedon a DL association set according to a DL HARQ reference configurationfor a given UL subframe of each configured eIMTA cell.

FIG. 4 is a diagram illustrating one example of a radio frame 435 thatmay be used in accordance with the systems and methods disclosed herein.This radio frame 435 structure illustrates a TDD structure. Each radioframe 435 may have a length of T_(f)=307200·T_(s)=10 ms, where T_(f) isa radio frame 435 duration and T_(s) is a time unit equal to

$\frac{1}{\left( {15000 \times 2048} \right)}$

seconds. The radio frame 435 may include two half-frames 437, eachhaving a length of 153600·T_(s)=5 ms. Each half-frame 437 may includefive subframes 423 a-e, 423 f-j each having a length of 30720·T_(s)=1ms.

TDD UL/DL configurations 0-6 are given below in Table (1) (from Table4.2-2 in 3GPP TS 36.211). UL/DL configurations with both 5 ms and 10 msdownlink-to-uplink switch-point periodicity may be supported. Inparticular, seven UL/DL configurations are specified in 3GPPspecifications, as shown in Table (1) below. In Table (1), “D” denotes adownlink subframe, “S” denotes a special subframe and “U” denotes a ULsubframe.

TABLE (1) TDD UL/ Downlink- DL Con- to-Uplink figuration Switch-PointSubframe Number Number Periodicity 0 1 2 3 4 5 6 7 8 9 0 5 ms D S U U UD S U U U 1 5 ms D S U U D D S U U D 2 5 ms D S U D D D S U D D 3 10 ms D S U U U D D D D D 4 10 ms  D S U U D D D D D D 5 10 ms  D S U D D D DD D D 6 5 ms D S U U U D S U U D

In Table (1) above, for each subframe in a radio frame, “D” indicatesthat the subframe is reserved for downlink transmissions, “U” indicatesthat the subframe is reserved for uplink transmissions and “S” indicatesa special subframe with three fields: a downlink pilot time slot(DwPTS), a guard period (GP) and an uplink pilot time slot (UpPTS). Thelength of DwPTS and UpPTS is given in Table (2) (from Table 4.2-1 of3GPP TS 36.211) subject to the total length of DwPTS, GP and UpPTS beingequal to 30720·T_(s)=1 ms. Table (2) illustrates several configurationsof (standard) special subframes. Each subframe i is defined as twoslots, 2i and 2i+1 of length T_(slot)=15360·T_(s)=0.5 ms in eachsubframe. In Table (2), “cyclic prefix” is abbreviated as “CP” and“configuration” is abbreviated as “Config” for convenience.

TABLE (2) Normal CP in downlink Extended CP in downlink Special UpPTSUpPTS Subframe Normal Extended Normal Extended Config DwPTS CP in uplinkCP in uplink DwPTS CP in uplink CP in uplink 0  6592 · T_(s) 2192 ·T_(s) 2560 · T_(s)  7680 · T_(s) 2192 · T_(s) 2560 · T_(s) 1 19760 ·T_(s) 20480 · T_(s) 2 21952 · T_(s) 23040 · T_(s) 3 24144 · T_(s) 25600· T_(s) 4 26336 · T_(s)  7680 · T_(s) 4384 · T_(s) 5120 · T_(s) 5  6592· T_(s) 4384 · T_(s) 5120 · T_(s) 20480 · T_(s) 6 19760 · T_(s) 23040 ·T_(s) 7 21952 · T_(s) — — — 8 24144 · T_(s) — — —

UL/DL configurations with both 5 ms and 10 ms downlink-to-uplinkswitch-point periodicity are supported. In the case of 5 msdownlink-to-uplink switch-point periodicity, the special subframe existsin both half-frames 437. In the case of 10 ms downlink-to-uplinkswitch-point periodicity, the special subframe exists in the firsthalf-frame 437 only. Subframes 0 and 5 and DwPTS may be reserved fordownlink transmission. UpPTS and the subframe immediately following thespecial subframe may be reserved for uplink transmission.

In accordance with the systems and methods disclosed herein, some typesof subframes 423 that may be used include a downlink subframe, an uplinksubframe and a special subframe 431. In the example illustrated in FIG.4, which has a 5 ms periodicity, two standard special subframes 431 a-bare included in the radio frame 435.

The first special subframe 431 a includes a downlink pilot time slot(DwPTS) 425 a, a guard period (GP) 427 a and an uplink pilot time slot(UpPTS) 429 a. In this example, the first standard special subframe 431a is included in subframe one 423 b. The second standard specialsubframe 431 b includes a downlink pilot time slot (DwPTS) 425 b, aguard period (GP) 427 b and an uplink pilot time slot (UpPTS) 429 b. Inthis example, the second standard special subframe 431 b is included insubframe six 423 g. The length of the DwPTS 425 a-b and UpPTS 429 a-bmay be given by Table 4.2-1 of 3GPP TS 36.211 (illustrated in Table (2)above) subject to the total length of each set of DwPTS 425, GP 427 andUpPTS 429 being equal to 30720·T_(s)=1 ms.

Each subframe i 423 a-j (where i denotes a subframe ranging fromsubframe zero 423 a (e.g., 0) to subframe nine 423 j (e.g., 9) in thisexample) is defined as two slots, 2i and 2i+1 of lengthT_(slot)=15360·T_(s)=0.5 ms in each subframe 423. For example, subframezero (e.g., 0) 423 a may include two slots, including a first slot 439.

UL/DL configurations with both 5 ms and 10 ms downlink-to-uplinkswitch-point periodicity may be used in accordance with the systems andmethods disclosed herein. FIG. 4 illustrates one example of a radioframe 435 with 5 ms switch-point periodicity. In the case of 5 msdownlink-to-uplink switch-point periodicity, each half-frame 437includes a standard special subframe 431 a-b. In the case of 10 msdownlink-to-uplink switch-point periodicity, a special subframe 431 mayexist in the first half-frame 437 only.

Subframe zero (e.g., 0) 423 a and subframe five (e.g., 5) 423 f andDwPTS 425 a-b may be reserved for DL transmission. The UpPTS 429 a-b andthe subframe(s) immediately following the standard special subframe(s)431 a-b (e.g., subframe two 423 c and subframe seven 423 h) may bereserved for UL transmission. In one implementation, in a case wheremultiple cells are aggregated, a UE 102 may assume the same UL/DLconfiguration across all the cells and that the guard period (GP) of thespecial subframe(s) in the different cells have an overlap of at least1456·T_(s).

One or more of the subframes 423 illustrated in FIG. 4 may beconvertible, depending on the UL/DL reconfiguration range. Assuming adefault UL/DL configuration 1 as given in Table (1) above, for example,subframe three (e.g., 3) 423 d may be a convertible subframe 433 (fromUL-to-DL, for instance).

FIG. 5 is a diagram illustrating TDD UL/DL configurations 541 a-g inaccordance with the systems and methods described herein. In particular,FIG. 5 illustrates UL/DL configuration zero 541 a (e.g., “UL/DLconfiguration 0”) with subframes 523 a and subframe numbers 543 a, UL/DLconfiguration one 541 b (e.g., “UL/DL configuration 1”) with subframes523 b and subframe numbers 543 b, UL/DL configuration two 541 c (e.g.,“UL/DL configuration 2”) with subframes 523 c and subframe numbers 543 cand UL/DL configuration three 541 d (e.g., “UL/DL configuration 3”) withsubframes 523 d and subframe numbers 543 d. FIG. 5 also illustratesUL/DL configuration four 541 e (e.g., “UL/DL configuration 4”) withsubframes 523 e and subframe numbers 543 e, UL/DL configuration five 541f (e.g., “UL/DL configuration 5”) with subframes 523 f and subframenumbers 543 f and UL/DL configuration six 541 g (e.g., “UL/DLconfiguration 6”) with subframes 523 g and subframe numbers 543 g.

Furthermore, FIG. 5 illustrates PDSCH HARQ-ACK associations 545 (e.g.,PDSCH HARQ-ACK feedback on PUCCH or PUSCH associations). The PDSCHHARQ-ACK associations 545 may indicate HARQ-ACK reporting subframescorresponding to subframes for PDSCH transmissions (e.g., subframes inwhich PDSCH transmissions may be sent and/or received). The PDSCHHARQ-ACK associations 545 may indicate the association sets and timingfor the transmission of PDSCH HARQ-ACK information. It should be notedthat some of the radio frames illustrated in FIG. 5 have been truncatedfor convenience.

The systems and methods described herein may be applied to one or moreof the UL/DL configurations 541 a-g illustrated in FIG. 5. For example,one or more PDSCH HARQ-ACK associations 545 corresponding to one of theUL/DL configurations 541 a-g illustrated in FIG. 5 may be applied tocommunications between a UE 102 and eNB 160. For example, a DL-referenceUL/DL configuration 541 may be determined (e.g., assigned to, appliedto) for a serving cell. In this case, PDSCH HARQ-ACK associations 545may specify PDSCH HARQ-ACK timing (e.g., a HARQ-ACK reporting subframe)for HARQ-ACK feedback transmissions corresponding to the serving cell.

A PDSCH HARQ-ACK association 545 may specify a particular (PDSCHHARQ-ACK) timing for receiving HARQ-ACK information corresponding to aPDSCH. A PDSCH HARQ-ACK association 545 may specify a reporting subframein which the UE 102 reports (e.g., transmits) the HARQ-ACK informationcorresponding to the PDSCH to the eNB 160. The reporting subframe may bedetermined based on the subframe that includes the PDSCH sent by the eNB160.

FIG. 6 is a flow diagram illustrating another implementation of a method600 for feedback reporting by a UE 102. The UE 102 may decode 602 aUL/DL reconfiguration DCI with an eIMTA-RNTI on a PDCCH/EPDCCH. In someimplementations, the UL/DL reconfiguration DCI is carried on the commonsearch space (CSS). The UL/DL reconfiguration DCI with an eIMTA-RNTI maybe received from an eNB 160. In some implementations, eIMTA may provideflexible use of spectrum using dynamic UL/DL allocation based on trafficload. Explicit L1 reconfiguration signaling may be used to indicate theactual TDD UL/DL configuration by group-common DCI only in a PCellcommon search space for a UE 102. The size of DCI that carriesreconfiguration bits may be aligned to DCI format 1C. The number ofeIMTA-RNTI configured for a UE 102 may be 1. The eIMTA-RNTI may beUE-specifically configured via RRC. Different UEs 102 may be configuredwith different eIMTA-RNTIs. The explicit reconfiguration DCI may onlycarry information for explicit UL/DL reconfiguration.

A reconfiguration window may be configured with periodicity of 10milliseconds (ms), 20 ms, 40 ms and/or 80 ms. The set of subframes thata UE 102 is configured to monitor for reconfiguration signaling may bebased on these periodicities. For a 10 ms periodicity, the set ofsubframes may be the DL subframes and special subframes per SIB1. For a20 ms periodicity, the set of subframes may be the DL subframes andspecial subframes per SIB1 in the second radio frame in the window. Fora 40 ms periodicity, the set of subframes may be the DL subframes andspecial subframes per SIB1 in the fourth radio frame in the window. Foran 80 ms periodicity, the set of subframes may be the DL subframes andspecial subframes per SIB1 in the eighth radio frame in the window.

If a UE 102 is configured to monitor multiple subframes forreconfiguration DCIs in radio frames {m·T/10, m·T/10+1, . . . ,(m+1)·T/10−1}, the UE 102 may assume the same UL/DL configurationindicated by the reconfiguration DCIs for radio frames {m·T/10,m·T/10+1, . . . , (m+1)·T/10−1}. As used herein, the same UL/DLconfiguration refers to any cell configured for the UE 102 with eIMTAenabled.

In one implementation, the UE 102 is required to monitor all subframesto carry reconfiguration DCI(s) for radio frames {m·T/10, m·T/10+1, . .. , (m+1)·T/10−1} at least until one valid UL-DL configuration for radioframes {m·T/10, m·T/10+1, . . . , (m+1)·T/10−1} is detected (e.g.,received).

If the UE 102 detects L1 signaling conveying a valid UL/DL configurationfor a radio frame, the UE 102 may monitor the non-discontinuousreception (DRX) DL subframes or special subframes indicated by explicitL1 signaling, referred to herein as normal operation (e.g., the UE 102follows 606 a normal mode of operation). If the UE 102 does not detectL1 signaling conveying a valid UL/DL configuration for a radio frame,the UE 102 may monitor the non-DRX DL subframes or special subframes forPDCCH or EPDCCH as indicated by an SIB1 configuration, referred toherein as fallback mode operation (e.g., the UE 102 follows 608 afallback mode of operation).

Under fallback operation, if the UE 102 receives a UL grantcorresponding to at least one UL subframe per a SIB1 not in the set ofUL subframes per the DL HARQ reference configuration, then the UE 102may still treat the UL grant as a valid UL grant. Also, under fallbackoperation, if the UE 102 receives a NACK in a PHICH triggering a PUSCHtransmission in a UL subframe per a SIB1 not in the set of UL subframesper the DL HARQ reference configuration, the UE 102 may transmit a PUSCHtransmission.

For PDSCH HARQ-ACK timing, the DL HARQ-ACK timing may follow a higherlayer RRC configured TDD configuration chosen from UL/DL configurations#2, #4 and #5, described above in connection with FIG. 5. HARQ-ACKbundling may not be supported for HARQ-ACK feedback for TDD eIMTA. PUCCHformat 3 and PUCCH format 1b with channel selection may be supported foreIMTA.

According to one approach for PDCCH scheduling, the existing implicitPUCCH resource for subframes with the same DL HARQ timing may be reusedbetween eIMTA and non-eIMTA UEs 102. New resources for other subframesmay be allocated in the bundling window. The new resources may be basedon a starting PUCCH offset that is separately configured via RRC. Theblock interleaving for ACK/NAK resource indexing may still be supported.

If TDD eIMTA is not enabled on the PCell but is enabled on at least oneSCell, then the UE 102 behavior for HARQ-ACK feedback when PUCCH format3 is configured may follow the HARQ-ACK feedback as specified inRelease-10 or 11.

While the above approach describes fallback mode behavior and DLHARQ-ACK timing, the approach does not specify detailed HARQ-ACKreporting on PUCCH. In particular, the described approach does notprovide for HARQ-ACK fallback operation to format 1a/1b when PUCCHformat 3 is configured. Additionally, the described approach does notspecify the number of HARQ-ACK bits to be reported on PUCCH format 3.

A UE 102 operating according to the systems and methods described hereinmay minimize the HARQ-ACK payload under normal mode and fallback modeoperation. Furthermore, the described systems and methods provide forimplicitly reporting the detection of reconfiguration signaling by PUCCHchannel selection. If the UE 102 does not detect a reconfiguration DCIwith eIMTA-RNTI in a PCell PDCCH common search space (CSS), the HARQ-ACKmay be reported on a different PUCCH resource than the PUCCH resourceused during normal operation.

HARQ-ACK reporting may be performed according to differentimplementations. In one implementation, the number of HARQ-ACK bits maybe determined by the DL HARQ reference configuration. Thisimplementation may result in an unnecessarily large HARQ-ACK payload,which may reduce PUCCH performance. In another implementation, thenumber of HARQ-ACK bits may be determined by the DL and specialsubframes according to the UL/DL configuration in the reconfigurationDCI. However, there may be ambiguity issues if the UE 102 does notdetect the PHY reconfiguration DCI correctly and performs a fallbackmode operation.

In one approach, an ACK/NACK bit for the PHY reconfiguration DCI may bereported together with the HARQ-ACK bits. However, this may increase theHARQ-ACK payload, may impact the total number of bits reported on aPUCCH, and may impact the maximum number of cells that can be configuredfor a UE 102.

The systems and methods described herein provide for implicit feedbackfor the reconfiguration DCI. Compared with the approach described above,the PUCCH resource selection described herein may also reduce the totalHARQ-ACK payload. In particular, the HARQ-ACK payload may be reducedwhen the reconfiguration DCI is not correctly received by the UE 102.

As described above, for an eIMTA cell, the reconfiguration window can beconfigured with different periodicities (e.g., 10 ms, 20 ms, 40 ms and80 ms). For an uplink subframe n with PUCCH HARQ-ACK report, thedetection status of the reconfiguration DCI with eIMTA-RNTI may bedetermined based on all reconfiguration DCI signals included in the DLassociation set of the given uplink subframe according to the DL HARQreference configuration.

For each eIMTA cell, if the subframes in the DL association set of thegiven uplink subframe according to the DL HARQ reference configurationbelong to one reconfiguration period, the status of the reconfigurationDCI with eIMTA-RNTI may be based on whether a valid UL/DL configurationin the reconfiguration DCI with eIMTA-RNTI for the given reconfigurationperiod is detected (e.g., received) or not.

For each eIMTA cell, if the subframes in the DL association set of thegiven uplink subframe according to the DL HARQ reference configurationbelong to two reconfiguration periods, the status of the reconfigurationDCI with eIMTA-RNTI may be based on whether valid UL/DL configurationsin all the reconfiguration DCI signals with eIMTA-RNTI for the tworeconfiguration periods are detected or not. If a valid UL/DLconfiguration is not detected in either of the two reconfiguration DCIsignals, valid UL/DL configuration in the reconfiguration DCI witheIMTA-RNTI is considered as not detected.

If there is more than one eIMTA cell configured, the eIMTA cell may beconfigured with different periodicities. A reconfiguration DCI witheIMTA-RNTI may include reconfiguration signals of multiple eIMTA cellsand is signaled on the PCell CSS only.

If there is more than one eIMTA cell configured, for the PUCCH reportingin a given uplink subframe, valid UL/DL configurations in thereconfiguration DCI with eIMTA-RNTI are considered as detected if validUL/DL configurations in the reconfiguration DCI signals for all eIMTAcells are correctly detected based on the DL association set of theuplink of each eIMTA cell. Furthermore, valid UL/DL configurations inthe reconfiguration DCI with eIMTA-RNTI are considered as not detectedif a valid UL/DL configuration in the reconfiguration DCI signal of anyeIMTA cell is not detected based on the DL association set of the uplinkof the eIMTA cell.

For an eIMTA cell operating according to the systems and methodsdescribed herein, PDSCH HARQ-ACK reporting may follow the DL-referenceUL/DL configuration of the serving cell to determine the DL associationset, as in Table (3) (from Table 10.1.3.1-1 of 3GPP TS 36.213). Table(3) provides a downlink association set index K: {k₀, k₁, . . .k_(M-1)}.

TABLE (3) UL/DL Config- Subframe n uration 0 1 2 3 4 5 6 7 8 9 0 — — 6 —4 — — 6 — 4 1 — — 7, 6 4 — — — 7, 6 4 — 2 — — 8, 7, 4, 6 — — — — 8, 7, —— 4, 6 3 — — 7, 6, 11 6, 5 5, 4 — — — — — 4 — — 12, 8, 6, 5, — — — — — —7, 11 4, 7 5 — — 13, 12, 9, — — — — — — — 8, 7, 5, 4, 11, 6 6 — — 7 7 5— — 7 7 —

As one way to report the PDSCH HARQ-ACK, the number of subframesincluded in the PDSCH HARQ-ACK reporting should be M_(DL-Ref), whereM_(DL-Ref) is the number of elements in the DL association set K definedin Table (3) for the DL HARQ reference UL/DL configuration of the eIMTAcell. This may provide the correct understanding between the eNB 160 andthe UE 102. On the other hand, the number of PDSCH HARQ-ACK bits maybecome large because all M_(DL-Ref) subframes in the DL association setshould be included in the report. The number of PDSCH HARQ-ACK bits maybecome very large if UL/DL configuration 5 is used as the DL-referenceUL/DL configuration. Furthermore, the traditional PDSCH HARQ-ACKreporting cannot indicate whether the UL/DL reconfiguration signaling iscorrectly received or not.

If the UE 102 receives the reconfiguration signaling correctly, the UE102 knows the DL and special subframes in the DL association setaccording to the UL/DL configuration in the reconfiguration DCI. In oneimplementation, M_(Reconfig-DCI) may be defined as the number of DL andspecial subframes according to the UL/DL configuration in thereconfiguration DCI in the set K defined in Table (3) for the DL HARQreference UL/DL configuration of the eIMTA cell. Thus, the UE 102 mayreport the HARQ-ACK based on the DL and special subframes correspondingto the reconfiguration DCI. In other words, the UE 102 may report theHARQ-ACK based on M_(Reconfig-DCI) instead of using M_(DL-Ref) for allsubframes in the association set.

It should be noted that the number of DL and special subframes in a DLassociation may be different from the current or the previous UL/DLconfiguration if the DL association set includes subframes withdifferent UL/DL configurations due to reconfiguration. Therefore, the UE102 may use the number of DL and special subframes according to theUL/DL configuration in the reconfiguration DCI in each association setin the PDSCH HARQ-ACK report if the eNB 160 knows that the UE 102correctly detects the reconfiguration signaling. Thus, feedback from theUE 102 to the eNB 160 may indicate whether the UE 102 detects thereconfiguration DCI. It should also be noted that in someimplementations, the UE 102 may not follow M_(Reconfig-DCI). It ispossible for the UE 102 to use M_(DL-Ref) even if the UE 102 receivesthe reconfiguration DCI correctly.

The UE 102 may determine 604 whether valid UL/DL configurations in theUL/DL reconfiguration DCI with eIMTA-RNTI for all of the configuredeIMTA cells corresponding to a subframe for the PUCCH resource arereceived. The UE 102 may operate according to normal and fallback modesof operation. If the UE 102 determines 604 that valid UL/DLconfigurations in the UL/DL reconfiguration DCI with eIMTA-RNTI of allconfigured eIMTA cells corresponding to a subframe for the PUCCHresource are detected (e.g., received), then the UE 102 may follow 606 anormal mode of operation.

While in a normal mode of operation, the UE 102 may minimize theHARQ-ACK bits on a PUCCH or PUSCH feedback. If one or more valid UL/DLconfigurations in the reconfiguration DCI with eIMTA-RNTI on the PCellCSS are detected, and if the UE 102 is configured with PUCCH format 3,then the UE 102 may determine the number of HARQ-ACK bits based on theDL and special subframes according to the UL/DL configuration in thereconfiguration DCI in the given DL association set. Thus, if the eIMTAcell is a SCell, if the UE 102 detects any PDSCH transmission targetedto the UE 102 on the SCell, the HARQ-ACK bits of all cells may bereported on PUCCH format 3. Also, if the eIMTA cell is a PCell, if theUE 102 detects more than one PDSCH transmission, except the SPS ifconfigured, then the HARQ-ACK of all cells may be reported on PUCCHformat 3.

The PUCCH format 3 resource may be configured by higher layer signalingand may be indicated by the TPC field if the PDSCH is scheduled by aPDCCH on a PCell or a PDCCH/EPDCCH on a SCell. The PUCCH format 3resource may be configured by higher layer signaling and indicated bythe HARQ-ACK resource offset (e.g., ARO) bits if the PDSCH is scheduledby an EPDCCH on the PCell. This may be accomplished as described inconnection with FIG. 7.

While in a normal mode of operation (e.g., when valid UL/DLconfigurations in the UL/DL reconfiguration DCI with eIMTA-RNTI of allconfigured eIMTA cells corresponding to a subframe for the PUCCHresource are detected), if there is only one PDSCH with a DAI value of 1in a PDCCH or EPDCCH that is detected on the PCell, a HARQ-ACK fallbackmode may be used. In this case, if the eIMTA cell is a PCell, and ifthere is only a SPS subframe detected, or if there is only one PDSCHdetected with a DAI value of 1 in a PDCCH or EPDCCH on the PCell only,the HARQ-ACK bits may be reported with a PUCCH format 1a/1b instead ofPUCCH format 3.

The DAI may be a field in the downlink resource grant that is signaledto the UE 102. The DAI may indicate how many subframes in a previoustime window contained transmissions to the UE 102. Using the DAI, the UE102 may determine whether it has received all the downlink transportblocks for which it should transmit HARQ-ACK feedback.

The PUCCH format 1a/1b resource may be determined (e.g., selected) bythe PUCCH resource allocation procedures defined for eIMTA. For example,the PUCCH resources for the fixed DL and special subframes in an SIB1configuration may be mapped according to Rel-8/9/10/11/12 UEs 102. A newPUCCH resource region and subframe interleaver may be applied for thePUCCH resource mapping of the remaining DL and special subframesspecified by UL/DL configuration in the reconfiguration DCI or the DLHARQ reference configuration.

If the UE 102 determines 604 that at least one valid UL/DL configurationin the UL/DL reconfiguration DCI with eIMTA-RNTI for at least oneconfigured eIMTA cell corresponding to a subframe for the PUCCH resourceis not detected, then the UE 102 may follow 608 a fallback mode ofoperation. If a valid UL/DL configuration in the reconfiguration DCIwith eIMTA-RNTI on the PCell CSS is not detected, the UE 102 may performfallback mode operation by monitoring the DL and special subframesspecified by the SIB1 configuration only. In this case, some PDSCHtransmissions may be missed by the UE 102. Therefore, the UE 102 may notbe able to report the HARQ-ACK bits correctly since the UE 102 does notknow the actual subframe allocation.

If valid UL/DL configuration in the reconfiguration DCI with eIMTA-RNTIon the PCell CSS is not detected, and if the UE 102 is configured withPUCCH format 3, the PUCCH report may use a different PUCCH resource fromthe normal mode operation. In one implementation, the PUCCH resource maybe determined (e.g., selected) by an offset value. As used herein, “anoffset value” refers to a fixed or predefined value (e.g., +1) to pointto another PUCCH resource. The offset value may be a fixed or predefinedvalue with modular 4 operation to determine the PUCCH resource index ofthe four PUCCH resource values configured by higher layers.

In another implementation, the PUCCH resource may be determined by aseparately configured PUCCH resource. As used herein, “a separatelyconfigured PUCCH resource” refers to a separate PUCCH resource that canbe configured by higher layer signaling (e.g., RRC signaling).

The PUCCH resource selection implicitly reports whether valid UL/DLconfiguration in the reconfiguration DCI is detected or not by the UE102. For example, the use of one PUCCH resource may indicate that the UE102 detected valid UL/DL configurations in the reconfiguration DCI,while the use of another PUCCH resource may indicate that the UE 102 didnot detect one or more valid UL/DL configurations in the reconfigurationDCI. Detailed PUCCH resource mapping with an offset or a separatelyconfigured PUCCH resource is described below in connection with FIG. 8.

If the reconfiguration DCI with eIMTA-RNTI on PCell CSS is not correctlydetected, the PUCCH resource used for HARQ-ACK reporting can bedetermined by a fixed or predefined offset (e.g., +1) over the normalPUCCH resource, or can be configured by higher layer signaling.

In one implementation, if the eIMTA cell is an SCell and if the UE 102detects any PDSCH transmission targeted to the UE 102 on an SCell, theHARQ-ACK information of all cells may be reported on PUCCH format 3.Also, if the eIMTA cell is a PCell and if the UE 102 detects more thanone PDSCH transmission (excluding the SPS, if configured), the HARQ-ACKinformation of all cells may be reported on PUCCH format 3. The normalPUCCH format 3 resource may be configured by higher layer signaling andmay be indicated by the TPC field (i.e. an ARI) if the PDSCH isscheduled by a PDCCH, or the TPC field and ARO bits if the PDSCH isscheduled by an EPDCCH.

If one or more valid UL/DL configurations in the reconfiguration DCIwith eIMTA-RNTI on the PCell CSS are not detected, the actual DL andspecial subframe allocation is unknown to the UE 102 according to theUL/DL configuration in the reconfiguration DCI. In this case, the UE 102may monitor only the DL and special subframes specified by the SIB1configuration. Since some subframes are not monitored, there may bemismatch on the DAI values. During fallback operation, the UE 102 mayperform HARQ-ACK reporting on PUCCH format 3 if valid UL/DLconfiguration in the reconfiguration DCI with eIMTA-RNTI on the PCellCSS is not detected.

In one approach for HARQ-ACK reporting on PUCCH format 3 if valid UL/DLconfiguration in the reconfiguration DCI with eIMTA-RNTI on the PCellCSS is not detected, the UE 102 may report HARQ-ACK bits based on the DLor special subframes defined by the DL HARQ reference configuration. TheHARQ-ACK bits may be ordered based on the detected DAI values. NACK maybe padded for the missing DAI values and the HARQ-ACK bits for theremaining subframes for all subframes in the DL association set given bythe DL HARQ reference configuration. This approach ensures a correctinterpretation of the DAI bits by the eNB 160. However, this approachmay utilize a higher HARQ-ACK payload, which may require more PUCCHtransmission power.

In a second approach for HARQ-ACK reporting on PUCCH format 3 if validUL/DL configuration in the reconfiguration DCI with eIMTA-RNTI on thePCell CSS is not detected, the UE 102 may report the HARQ-ACK bits basedon subframe allocation of the SIB1 configuration. Thus, in the DLassociation set given by the DL HARQ reference configuration, only thefixed DL and special subframes indicated by SIB1 configuration arereported.

In one implementation, the HARQ-ACK bits are ordered based on thedetected DAI values, NACK is padded for the remaining bits for all fixedDL or special subframes only. This implementation provides the minimumHARQ-ACK payload on a PUCCH reporting. In some cases of mismatch of DAIvalues (e.g., some missing DAI values before or between detected PDSCHtransmissions), no NACK may be added.

In another implementation, the DAI values can be ignored, and theHARQ-ACK bits may be reported for all the fixed DL and special subframesin the DL association set following the subframe ordering in timing, orthe subframe ordering according to the DL association set. A NACK bitmay be added if there is no PDSCH detected in a fixed DL or specialsubframe in the DL association set.

In some scenarios, the HARQ-ACK bits may be reported with PUCCH format1a/1b instead of PUCCH format 3. If a valid UL/DL configuration in thereconfiguration DCI with eIMTA-RNTI on the PCell CSS is not detected,the HARQ-ACK fallback mode may also be used if there is only one PDSCHwith a DAI value of 1 that is detected on the PCell. Therefore, if theeIMTA cell is a PCell, if there is only a SPS subframe detected, or ifthere is only one PDSCH detected with a DAI value of 1 on the PCellonly, the HARQ-ACK bits may be reported with PUCCH format 1a/1b insteadof PUCCH format 3.

Three alternatives may be considered for the PUCCH format 1a/1bresource. With a first alternative, a different PUCCH 1a/1b resourcefrom the normal operation PUCCH resource may be used to carrier theHARQ-ACK. If a valid UL/DL configuration in the reconfiguration DCI witheIMTA-RNTI on the PCell CSS is not detected, the PUCCH format 1a/1bresource may be determined by the normal PUCCH 1a/1b resource allocationprocedures defined for eIMTA and an offset value. The offset value canbe a fixed or predefined value (e.g., +1) pointing to another PUCCHresource. In a second alternative, if a valid UL/DL configuration in thereconfiguration DCI with eIMTA-RNTI on the PCell CSS is not detected,the PUCCH format 1a/1b resource may be configured by higher layersignaling (e.g., RRC signaling). In a third alternative, none of a fixedor predefined value and a separate PUCCH resource is used. Instead, animplicit PUCCH format 1a/1b resource is used. In this third alternative,the UE 102 may follow the number of CCEs.

In yet another implementation, and without loss of generality, HARQ-ACKreporting of an eIMTA cell may also be performed by switching the normalmode operation and fallback mode operation described herein. In thisimplementation, if a valid UL/DL configuration in the reconfigurationDCI with eIMTA-RNTI on the PCell CSS is not detected (e.g., fallbackmode), the PUCCH format 3 resource may be determined by the TPC field(e.g., ARI) in the case of PDCCH scheduling, or the TPC field and ARO inthe case of EPDCCH scheduling. If valid UL/DL configurations in thereconfiguration DCI with eIMTA-RNTI on the PCell CSS are correctlydetected (e.g., normal mode), the PUCCH format 3 resource may bedetermined with an offset value. The offset can be a fixed or predefinednumber, or the offset may be RRC configured.

The benefits of the described systems and methods for HARQ-ACK reportingof an eIMTA cell include minimizing the HARQ-ACK payload on PUCCH. PUCCHresource selection may be utilized to feedback whether valid UL/DLconfiguration in the reconfiguration DCI with eIMTA-RNTI is detected ornot. The described systems and methods provide backward compatibleoperations and utilize shared resources with legacy UEs 102.

FIG. 7 is a flow diagram illustrating one implementation of a method 700for feedback reporting by a UE 102 while in a normal mode of operation.The UE 102 may decode 702 a UL/DL reconfiguration DCI with an eIMTA-RNTIon a PDCCH/EPDCCH. The UL/DL reconfiguration DCI with an eIMTA-RNTI maybe received from an eNB 160. Explicit reconfiguration signaling (e.g.,the reconfiguration DCI) may be used to indicate the actual TDD UL/DLconfiguration. The eIMTA-RNTI may be UE-specifically configured via RRC.Different UEs 102 may be configured with different eIMTA-RNTIs.

The UE 102 may determine 704 that valid UL/DL configurations in theUL/DL reconfiguration DCI with eIMTA-RNTI for all of the configuredeIMTA cells corresponding to a subframe for the PUCCH resource arereceived. The status of the reconfiguration DCI with eIMTA-RNTI may bebased on whether a valid UL/DL configuration in the reconfiguration DCIwith eIMTA-RNTI for a given reconfiguration period is detected (e.g.,received) or not. If the UE 102 determines 704 that valid UL/DLconfigurations in the UL/DL reconfiguration DCI with eIMTA-RNTI of allconfigured eIMTA cells corresponding to a subframe for the PUCCHresource are detected (e.g., received), then the UE 102 may follow anormal mode of operation.

The UE 102 may determine 706 the PUCCH resource based on at least one ofa TPC field (e.g., ARI) and an ARO. While in a normal mode of operation,the UE 102 may minimize the HARQ-ACK bits on a PUCCH or PUSCH feedback.

If one or more valid UL/DL configurations in the reconfiguration DCIwith eIMTA-RNTI on the PCell CSS are detected, and if the UE 102 isconfigured with PUCCH format 3, then the UE 102 may determine the numberof HARQ-ACK bits based on the DL and special subframes according to theUL/DL configuration in the reconfiguration DCI in the given DLassociation set. Thus, if the eIMTA cell is an SCell, and if the UE 102detects any PDSCH transmission targeted to the UE 102 on the SCell, theHARQ-ACK bits of all cells may be reported on PUCCH format 3. Also, ifthe eIMTA cell is a PCell, and if the UE detects more than one PDSCHtransmission, except the SPS if configured, HARQ-ACK of all cells may bereported on PUCCH format 3.

The PUCCH format 3 resource may be configured by higher layer signalingand may be indicated by the TPC field if the PDSCH is scheduled by aPDCCH on a PCell or an PDCCH/EPDCCH on a SCell. The PUCCH format 3resource may be configured by higher layer signaling and indicated bythe HARQ-ACK resource offset (e.g., ARO) bits if the PDSCH is scheduledby an EPDCCH on the PCell.

For a PDSCH transmission on an SCell indicated by the detection of acorresponding PDCCH, and for M>1 and a PDSCH transmission only on thePCell indicated by the detection of a corresponding PDCCH in subframen−k_(m), where k_(m)εK, with the DAI value in the PDCCH greater than 1or a PDCCH indicating downlink SPS release in subframe n−k_(m), wherek_(m)εK, with the DAI value in the PDCCH greater than 1, the UE 102 mayuse PUCCH format 3, PUCCH resource n_(PUCCH) ^((3,{tilde over (p)})) andthe TPC field in a PDCCH assignment with a DAI value greater than 1 todetermine the PUCCH resource value from one of the four PUCCH resourcevalues configured by higher layers, with the mapping defined in Table(4). The value of n_(PUCCH) ^((3,{tilde over (p)})) is determinedaccording to higher layer configuration and Table (4) (from 3GPP TS36.213, v. 11.4, table 10.1.2.2.2-1).

TABLE (4) Value of ‘TPC command for PUCCH’ or ‘HARQ- ACK resourceoffset’ n_(PUCCH) ^((3, {tilde over (p)})) ‘00’ The 1st PUCCH resourcevalue configured by the ligher layers ‘01’ The 2^(nd) PUCCH resourcevalue configured by the ligher layers ‘10’ The 3^(rd) PUCCH resourcevalue configured by the ligher layers ‘11’ The 4^(th) PUCCH resourcevalue configured by the ligher layers

A UE 102 may assume that the same HARQ-ACK PUCCH resource value istransmitted on all PDCCH assignments used to determine the PUCCHresource values within the subframe(s) n−k, where kεK.

For a PDSCH transmission on an SCell indicated by the detection of acorresponding EPDCCH, for M>1 and a PDSCH transmission only on the PCellindicated by the detection of a corresponding EPDCCH in subframen−k_(m), where k_(m)εK with the DAI value in the EPDCCH greater than 1or an EPDCCH indicating downlink SPS release in subframe n−k_(m), wherek_(m)εK with the DAI value in the EPDCCH greater than 1, the UE 102 mayuse PUCCH format 3, PUCCH resource n_(PUCCH) ^((3,{tilde over (p)}))(where the value of n_(PUCCH) ^((3,{tilde over (p)})) is determinedaccording to higher layer configuration and Table (4)) and the HARQ-ACKresource offset field in the DCI format of the corresponding EPDCCHassignment with DAI value greater than 1 to determine the PUCCH resourcevalue from one of the four PUCCH resource values configured by higherlayers, with the mapping defined in Table (4). A UE 102 may assume thatthe same HARQ-ACK PUCCH resource value is transmitted on all EPDCCHassignments used to determine the PUCCH resource values within thesubframe(s) n−k, where kεK.

If the UL/DL configurations of all serving cells are the same, for aPDSCH transmission on the SCell indicated by the detection of acorresponding PDCCH/EPDCCH within subframe(s) n−k, where kεK, the UE 102may use PUCCH format 3, PUCCH resource n_(PUCCH) ^((3,{tilde over (p)}))(where the value of n_(PUCCH) ^((3,{tilde over (p)})) is determinedaccording to higher layer configuration and Table (4)) and the TPC fieldin the corresponding PDCCH/EPDCCH to determine the PUCCH resource valuefrom one of the four resource values configured by higher layers, withthe mapping defined in Table (4).

For TDD UL/DL configurations 1-6, if a PDCCH corresponding to a PDSCH onthe PCell within subframe(s) n+k, where kεK, or a PDCCH indicatingdownlink SPS release within subframe(s) n+k, where kεK, is detected, theTPC field in the PDCCH with the DAI value greater than 1 may be used todetermine the PUCCH resource value from one of the four resource valuesconfigured by higher layers, with the mapping defined in Table (4). A UE102 may assume that the same HARQ-ACK PUCCH resource value istransmitted on all PDCCH assignments in the PCell and in each SCell thatare used to determine the PUCCH resource value within the subframe(s)n−k, where kεK.

For TDD UL/DL configurations 1-6, if an EPDCCH corresponding to a PDSCHon the primary cell within subframe(s) n+k, where kεK, or an EPDCCHindicating downlink SPS release within subframe(s) n−k, where kεK, isdetected, the HARQ-ACK resource offset field in the DCI format of thecorresponding EPDCCH assignment with the DAI value greater than 1 shallbe used to determine the PUCCH resource value from one of the fourresource values configured by higher layers, with the mapping defined inTable (4). A UE 102 may assume that the same HARQ-ACK PUCCH resourcevalue is transmitted on all EPDCCH assignments in the PCell and in eachSCell that are used to determine the PUCCH resource value within thesubframe(s) n−k, where kεK.

If the UL/DL configurations of at least two serving cells are different,for a PDSCH transmission on the SCell indicated by the detection of acorresponding PDCCH/EPDCCH within subframe(s) n−k, where kεK, the UE 102may use PUCCH format 3, PUCCH resource n_(PUCCH) ^((3,{tilde over (p)}))(where the value of n_(PUCCH) ^((3,{tilde over (p)})) is determinedaccording to higher layer configuration and Table (4)) and the TPC fieldin the corresponding PDCCH/EPDCCH to determine the PUCCH resource valuefrom one of the four resource values configured by higher layers, withthe mapping defined in Table (4).

For a UL/DL configuration of the PCell belonging to {1,2,3,4,5,6}, if aPDCCH corresponding to a PDSCH on the PCell within subframe(s) n−k,where kεK, or a PDCCH indicating downlink SPS release within subframe(s)n−k, where kεK, is detected, the TPC field in the PDCCH with the DAIvalue greater than 1 may be used to determine the PUCCH resource valuefrom one of the four resource values configured by higher layers, withthe mapping defined in Table (4). A UE 102 may assume that the sameHARQ-ACK PUCCH resource value is transmitted on all PDCCH assignments inthe PCell and in each SCell that are used to determine the PUCCHresource value within the subframe(s) n−k, where kεK.

Further, if the UL/DL configurations of at least two serving cells aredifferent, for a UL/DL configuration of the PCell belonging to{1,2,3,4,5,6}, if an EPDCCH corresponding to a PDSCH on the primary cellwithin subframe(s) n−k, where kεK, or an EPDCCH indicating downlink SPSrelease within subframe(s) n−k, where kεK, is detected, the HARQ-ACKresource offset field in the DCI format of the corresponding EPDCCHassignment with the DAI value greater than 1 may be used to determinethe PUCCH resource value from one of the four resource values configuredby higher layers, with the mapping defined in Table (4). A UE 102 mayassume that the same HARQ-ACK PUCCH resource value is transmitted on allEPDCCH assignments in the PCell and in each SCell that are used todetermine the PUCCH resource value within the subframe(s) n−k, wherekεK.

In the case where there is only one PDSCH with a DAI value of 1 in aPDCCH or EPDCCH that is detected on the PCell, a HARQ-ACK fallback modemay be used. Thus, if the eIMTA cell is a PCell, if there is only a SPSsubframe detected, or if there is only one PDSCH detected with a DAIvalue of 1 in a PDCCH or EPDCCH on the PCell only, the HARQ-ACK bits maybe reported with a PUCCH format 1a/1b instead of PUCCH format 3.

For a single PDSCH transmission only on the PCell indicated by thedetection of a corresponding PDCCH in subframe n−k_(m), where k_(m)εK,and for a TDD UL/DL configuration of the primary cell belonging to{1,2,3,4,5,6} the DAI value in the PDCCH is equal to 1, or for a PDCCHindicating downlink SPS release in subframe n−k_(m), where k_(m)εK, andfor a TDD UL/DL configuration of the PCell belonging to {1,2,3,4,5,6}the DAI value in the PDCCH is equal to 1, the UE 102 may use PUCCHformat 1a/1b and PUCCH resource n_(PUCCH) ^((1,{tilde over (p)})) withn_(PUCCH) ^((1,{tilde over (p)}))(M−m−1)·N_(c)+m·N_(c+1)+n_(CCE,m)+N_(PUCCH) ⁽¹⁾ for antenna port p₀. Inthis case, N_(PUCCH) ⁽¹⁾ is configured by higher layers, c is selectedfrom {0, 1, 2, 3} such that N_(c)≦n_(CCE,m)≦N_(c+1),

N_(c) = max {0, ⌊[N_(RB)^(DL) ⋅ (N_(sc)^(RB) ⋅ c − 4)]/36⌋},

and n_(CCE,m) is the number of the first CCE used for transmission ofthe corresponding PDCCH in subframe n−k_(m), where k_(m)εK. When a twoantenna port transmission is configured for PUCCH format 1a/1b, thePUCCH resource for antenna port p₁ is given by n_(PUCCH)^((1,{tilde over (p)}) ¹ ⁾=n_(PUCCH) ^((1,{tilde over (p)}) ⁰ ⁾+1.

For a single PDSCH transmission only on the PCell indicated by thedetection of a corresponding EPDCCH in subframe n−k_(m), where k_(m)εK,and for a TDD UL/DL configuration of the primary cell belonging to{1,2,3,4,5,6} the DAI value in the EPDCCH is equal to 1, or for a PDCCHindicating downlink SPS release in subframe n−k_(m), where k_(m)εK, andfor a TDD UL/DL configuration of the PCell belonging to {1,2,3,4,5,6}the DAI value in the EPDCCH is equal to 1, the UE 102 may use PUCCHformat 1a/1b and PUCCH resource n_(PUCCH) ^((1,{tilde over (p)})), givenby the following.

If EPDCCH-PRB-set q is configured for distributed transmission, then

$n_{PUCCH}^{({1,\overset{\sim}{p}})} = {n_{{ECCE},q} + {\sum\limits_{{i\; 1} = 0}^{m - 1}N_{{ECCE},q,{n - k_{i\; 1}}}} + \Delta_{ARO} + {N_{{PUCCH},q}^{({e\; 1})}.}}$

If EPDCCH-PRB-set q is configured for localized transmission, then

$n_{PUCCH}^{({1,\overset{\sim}{p}})} = {{\left\lfloor \frac{n_{{ECCE},q}}{N_{RB}^{{ECCE},q}} \right\rfloor \cdot N_{RB}^{{ECCE},q}} + {\sum\limits_{{i\; 1} = 0}^{m - 1}N_{{ECCE},q,{n - k_{i\; 1}}}} + n^{\prime} + \Delta_{ARO} + {N_{{PUCCH},q}^{({e\; 1})}.}}$

In this case, n_(ECCE,q) is the number of the first enhanced controlchannel element (ECCE) (i.e. the lowest ECCE index used to construct theEPDCCH) used for transmission of the corresponding DCI assignment inEPDCCH-PRB-set q in subframe n−k_(m), N_(PUCCH,q) ^((e1)) forEPDCCH-PRB-set q is configured by the higher layer parameterPUCCH-ResourceStartOffset-r11, and n′ is determined from the antennaport used for EPDCCH transmission in subframe n−k_(m).

If m=0, Δ_(ARO) is determined from the HARQ-ACK resource offset field inthe DCI format of the corresponding EPDCCH, as given in Table (5) (from3GPP TS 36.213, v. 11.4, table 10.1.2.1-1).

TABLE (5) ACK/NACK Resource offset field in DCI format1A/1B/1D/1/2A/2/2B/2C/2D Δ_(ARO) 0 0 1 −1 2 −2 3 2

If m>0, Δ_(ARO) is determined from the HARQ-ACK resource offset field inthe DCI format of the corresponding EPDCCH, as given in Table (6) (from3GPP TS 36.213, v. 11.4, table 10.1.3.1-2).

TABLE (6) ACK/NACK Resource offset field in DCI format1A/1B/1D/1/2A/2/2B/2C/2D Δ_(ARO) 0 0 1${- {\sum\limits_{{i\; 1} = 0}^{m - 1}N_{{ECCE},q,{n - k_{i\; 1}}}}} - 2$2${- {\sum\limits_{{i\; 1} = {m - {\lceil{m/3}\rceil}}}^{m - 1}N_{{ECCE},q,{n - k_{i\; 1}}}}} - 1$3 2

If the UE 102 is configured to monitor EPDCCH in subframe n−k_(i1),N_(ECCE,q,n−k) _(i1) is equal to the number of ECCEs in EPDCCH-PRB-set qconfigured for that UE 102 in subframe n−k_(i1). If the UE 102 is notconfigured to monitor EPDCCH in subframe n−k_(i1), N_(ECCE,q,n−k) _(i1)is equal to the number of ECCEs computed assuming EPDCCH-PRB-set q isconfigured for that UE 102 in subframe n−k_(i1).

For normal downlink cyclic prefix (CP), if subframe n−k _(i1) is aspecial subframe with special subframe configuration 0 or 5,N_(ECCE,q,n−k) _(i1) is equal to 0. For extended downlink CP, ifsubframe n−k_(i1) is a special subframe with special subframeconfiguration 0 or 4 or 7, N_(ECCE,q,n−k) _(i1) is equal to 0. When atwo antenna port transmission is configured for PUCCH format 1a/1b, thePUCCH resource for antenna port p₁ is given by n_(PUCCH)^((1,{tilde over (p)}) ¹ ⁾=n_(PUCCH) ^((1,{tilde over (p)}) ⁰ ⁾+1.

For a single PDSCH transmission only on the PCell where there is not acorresponding PDCCH/EPDCCH detected within subframe(s) n−k, where kεK,and no PDCCH/EPDCCH indicating downlink SPS release within subframe(s)n−k, where kεK, the UE 102 may use PUCCH format 1a/1b and PUCCH resourcen_(PUCCH) ^((1,{tilde over (p)})) with the value of n_(PUCCH)^((1,{tilde over (p)})) determined according to higher layerconfiguration. For a UE 102 configured for a two antenna porttransmission for PUCCH format 1a/1b, a PUCCH resource value in Table (7)(from 3GPP TS 36.213, v. 11.4, table 9.2-2) maps to two PUCCH resourceswith the first PUCCH resource n_(PUCCH) ^((1,{tilde over (p)}) ⁰ ⁾ forantenna port p₀ and the second PUCCH resource n_(PUCCH)^((1,{tilde over (p)}) ¹ ⁾ for antenna port p₁, otherwise, the PUCCHresource value maps to a single PUCCH resource n_(PUCCH)^((1,{tilde over (p)}) ¹ ⁾ for antenna port p₀.

TABLE (7) Value of ‘TPC command for PUCCH’ n_(PUCCH) ^((1, p)) ‘00’ Thefirst PUCCH resource value configured by the higher layers ‘01’ Thesecond PUCCH resource value configured by the higher layers ‘10’ Thethird PUCCH resource value configured by the higher layers ‘11’ Thefourth PUCCH resource value configured by the higher layers

For M>1 and a PDSCH transmission only on the PCell where there is not acorresponding PDCCH detected within subframe(s) n−k, where kεK and anadditional PDSCH transmission only on the PCell indicated by thedetection of a corresponding PDCCH in subframe n−k_(m), where k_(m)εKwith the DAI value in the PDCCH equal to 1 or a PDCCH indicatingdownlink SPS release in subframe n−k_(m), where k_(m)εK with the DAIvalue in the PDCCH equal to 1, the UE 102 may transmit b(0),b(1) insubframe n using PUCCH format 1b on PUCCH resource n_(PUCCH) ⁽¹⁾selected from A PUCCH resources n_(PUCCH,i) ⁽¹⁾ where 0≦i≦A−1, accordingto Table (8) (from 3GPP TS 36.213, v. 11.4, table 10.1.3.2-1) and Table(9) (from 3GPP TS 36.213, v. 11.4, table 10.1.3.2-2) for A=2 and A=3,respectively. For a UE 102 configured with a transmission mode thatsupports up to two transport blocks on the primary cell, A=3; otherwise,A=2.

TABLE (8) HARQ-ACK(0), HARQ-ACK(1) n_(PUCCH) ⁽¹⁾ b(0)b(1) ACK, ACKn_(PUCCH, 1) ⁽¹⁾ 1, 0 ACK, NACK/DTX n_(PUCCH, 0) ⁽¹⁾ 1, 1 NACK/DTX, ACKn_(PUCCH, 1) ⁽¹⁾ 0, 1 NACK, NACK/DTX n_(PUCCH, 0) ⁽¹⁾ 0, 0 DTX, NACK/DTXNo Transmission

TABLE (9) HARQ-ACK(0), HARQ-ACK(1), HARQ-ACK(2) n_(PUCCH) ⁽¹⁾ b(0)b(1)ACK, ACK, ACK n_(PUCCH, 2) ⁽¹⁾ 1, 1 ACK, ACK, NACK/DTX n_(PUCCH, 1) ⁽¹⁾1, 0 ACK, NACK/DTX, ACK n_(PUCCH, 2) ⁽¹⁾ 1, 0 ACK, NACK/DTX, NACK/DTXn_(PUCCH, 0) ⁽¹⁾ 1, 1 NACK/DTX, ACK, ACK n_(PUCCH, 2) ⁽¹⁾ 0, 1 NACK/DTX,ACK, NACK/DTX n_(PUCCH, 1) ⁽¹⁾ 0, 1 NACK/DTX, NACK/DTX, ACK n_(PUCCH, 2)⁽¹⁾ 0, 0 NACK, NACK/DTX, NACK/DTX n_(PUCCH, 0) ⁽¹⁾ 0, 0 DTX, NACK/DTX,NACK/DTX No Transmission

The PUCCH resource n_(PUCCH,0) ⁽¹⁾ is determined according to higherlayer configuration and Table (7). The PUCCH resource n_(PUCCH,1) ⁽¹⁾ isdetermined as n_(PUCCH,1)⁽¹⁾=(M−m−1)·N_(c)+m·N_(c+1)+n_(CCE,m)+N_(PUCCH) ⁽¹⁾, where N_(PUCCH) ⁽¹⁾is configured by higher layers, c is selected from {0, 1, 2, 3} suchthat N_(c)≦n_(CCE,m)<N_(c+1),

N_(c) = max {0, ⌊[N_(RB)^(DL) ⋅ (N_(sc)^(RB) ⋅ c − 4)]/36⌋},

and n_(CCE,m) is the number of the first CCE used for transmission ofthe corresponding PDCCH in subframe n−k_(m), where k_(m)εK.

For a UE 102 configured with a transmission mode that supports up to twotransport blocks on the PCell, the PUCCH resource n_(PUCCH,2) ⁽¹⁾ isdetermined as n_(PUCCH,2) ⁽¹⁾=n_(PUCCH,1) ⁽¹⁾+1. HARQ-ACK(0) is theACK/NACK/DTX response for the PDSCH without a corresponding PDCCHdetected. HARQ-ACK(1) is the ACK/NACK/DTX response for the firsttransport block of the PDSCH indicated by the detection of acorresponding PDCCH for which the value of the DAI field in thecorresponding DCI format is equal to 1 or for the PDCCH indicatingdownlink SPS release for which the value of the DAI field in thecorresponding DCI format is equal to 1. HARQ-ACK(2) is the ACK/NACK/DTXresponse for the second transport block of the PDSCH indicated by thedetection of a corresponding PDCCH for which the value of the DAI fieldin the corresponding DCI format is equal to 1.

For M>1 and a PDSCH transmission only on the PCell where there is not acorresponding EPDCCH detected within subframe(s) n−k, where kεK, and anadditional PDSCH transmission only on the PCell indicated by thedetection of a corresponding EPDCCH in subframe n−k_(m), where k_(m)εK,with the DAI value in the EPDCCH equal to 1 or an EPDCCH indicatingdownlink SPS release in subframe n−k_(m), where k_(m)εK with the DAIvalue in the EPDCCH equal to 1, the UE 102 may transmit b(0),b(1) insubframe n using PUCCH format 1b on PUCCH resource n_(PUCCH) ⁽¹⁾selected from A PUCCH resources n_(PUCCH,i) ⁽¹⁾ where 0≦i≦A−1, accordingto Table (8) and Table (9) for A=2 and A=3, respectively. For a UE 102configured with a transmission mode that supports up to two transportblocks on the primary cell, A=3; otherwise, A=2.

The PUCCH resource n_(PUCCH,0) ⁽¹⁾ is determined according to higherlayer configuration and Table (7). The PUCCH resource n_(PUCCH,1) ⁽¹⁾ isdetermined according to the following. If EPDCCH-PRB-set q is configuredfor distributed transmission, then

$n_{{PUCCH},1}^{(1)} = {n_{{ECCE},q} + {\sum\limits_{{i\; 1} = 0}^{m - 1}N_{{ECCE},q,{n - k_{i\; 1}}}} + \Delta_{ARO} + {N_{{PUCCH},q}^{({e\; 1})}.}}$

If EPDCCH-PRB-set q is configured for localized transmission, then

$n_{{PUCCH},1}^{(1)} = {{\left\lfloor \frac{n_{{ECCE},q}}{N_{RB}^{{ECCE},q}} \right\rfloor \cdot N_{RB}^{{ECCE},q}} + {\sum\limits_{{i\; 1} = 0}^{m - 1}N_{{ECCE},q,{n - k_{i\; 1}}}} + n^{\prime} + \Delta_{ARO} + {N_{{PUCCH},q}^{({e\; 1})}.}}$

In this case, n_(ECCE,q) is the number of the first ECCE (i.e., lowestECCE index used to construct the EPDCCH) used for transmission of thecorresponding DCI assignment in EPDCCH-PRB-set q in subframe n−k_(m),N_(PUCCH,q) ⁽¹⁾ for EPDCCH-PRB-set q is configured by the higher layerparameter PUCCH-ResourceStartOffset-r11, n′ is determined from theantenna port used for EPDCCH transmission in subframe n−k_(m).

If m=0, Δ_(ARO) is determined from the HARQ-ACK resource offset field inthe DCI format of the corresponding EPDCCH as given in Table (5). Ifm>0, Δ_(ARO) is determined from the HARQ-ACK resource offset field inthe DCI format of the corresponding EPDCCH as given in Table (6). If theUE 102 is configured to monitor EPDCCH in subframe n−k_(i1),N_(ECCE,q,n−k) _(i1) is equal to the number of ECCEs in EPDCCH-PRB-set qconfigured for that UE 102 in subframe n−k_(i1). If the UE 102 is notconfigured to monitor EPDCCH in subframe n−k_(i1), N_(ECCE,q,n−k) _(i1)is equal to the number of ECCEs computed assuming EPDCCH-PRB-set q isconfigured for that UE 102 in subframe n−k_(i1).

For normal downlink CP, if subframe n−k_(i1) is a special subframe withspecial subframe configuration 0 or 5, N_(ECCE,q,n−k) _(i1) is equal to0. For extended downlink CP, if subframe n−k_(i1) is a special subframewith special subframe configuration 0 or 4 or 7, N_(ECCE,q,n−k) _(i1) isequal to 0.

For a UE 102 configured with a transmission mode that supports up totwo) transport blocks on the primary cell, the PUCCH resourcen_(PUCCH,2) ⁽¹⁾ is determined as n_(PUCCH,2) ⁽¹⁾=n_(PUCCH,1) ⁽¹⁾+1.HARQ-ACK(0) is the ACK/NACK/DTX response for the PDSCH without acorresponding EPDCCH detected. HARQ-ACK(1) is the ACK/NACK/DTX responsefor the first transport block of the PDSCH indicated by the detection ofa corresponding EPDCCH for which the value of the DAI field in thecorresponding DCI format is equal to 1 or for the EPDCCH indicatingdownlink SPS release for which the value of the DAI field in thecorresponding DCI format is equal to 1. HARQ-ACK(2) is the ACK/NACK/DTXresponse for the second transport block of the PDSCH indicated by thedetection of a corresponding EPDCCH for which the value of the DAI fieldin the corresponding DCI format is equal to 1.

FIG. 8 is a flow diagram illustrating one implementation of a method 800for feedback reporting by a UE 102 while in a fallback mode ofoperation. The UE 102 may decode 802 a UL/DL reconfiguration DCI with aneIMTA-RNTI on a PDCCH/EPDCCH. The UL/DL reconfiguration DCI with aneIMTA-RNTI may be received from an eNB 160. Explicit reconfigurationsignaling (e.g., the reconfiguration DCI) may be used to indicate theactual TDD UL/DL configuration. The eIMTA-RNTI may be UE-specificallyconfigured via RRC. Different UEs 102 may be configured with differenteIMTA-RNTIs.

The UE 102 may determine 804 that at least one valid UL/DL configurationin the UL/DL reconfiguration DCI with eIMTA-RNTI for at least oneconfigured eIMTA cell corresponding to a subframe for the PUCCH resourceis not received. The UE 102 may follow a fallback mode of operation.

The UE 102 may operate in a fallback mode if a valid UL/DL configurationin the reconfiguration DCI with eIMTA-RNTI is not detected. If a validUL/DL configuration in the reconfiguration DCI with eIMTA-RNTI on thePCell CSS is not detected, the UE 102 may perform fallback modeoperation by monitoring the DL and special subframes specified by theSIB1 configuration only. In this case, some PDSCH transmissions may bemissed by the UE 102. Therefore, the UE 102 may not be able to reportthe HARQ-ACK bits correctly since the UE 102 does not know the actualsubframe allocation.

The UE 102 may determine 806 the PUCCH resource based on at least one ofa predefined offset or a separate PUCCH resource. If valid UL/DLconfiguration in the reconfiguration DCI with eIMTA-RNTI on the PCellCSS is not detected, and if the UE 102 is configured with PUCCH format3, the PUCCH report may use a different PUCCH resource from the normalmode operation. In one implementation, the PUCCH resource may bedetermined (e.g., selected) by an offset value. The offset value may bea fixed or predefined value with modular 4 operation to determine thePUCCH resource index of the four PUCCH resource values configured byhigher layers. In another implementation, the PUCCH resource may bedetermined by a separately configured PUCCH resource.

For a PDSCH transmission on an SCell indicated by the detection of acorresponding PDCCH, and for M>1 and a PDSCH transmission only on thePCell indicated by the detection of a corresponding PDCCH in subframen−k_(m), where k_(m)εK, with the DAI value in the PDCCH greater than 1or a PDCCH indicating downlink SPS release in subframe n−k_(m), wherek_(m)εK, with the DAI value in the PDCCH greater than 1, the UE 102 mayuse PUCCH format 3, PUCCH resource n_(PUCCH) ^((3,{tilde over (p)})) andthe TPC field in a PDCCH assignment with DAI value greater than 1 may beused to determine the PUCCH resource value from one of the four PUCCHresource values configured by higher layers, with the mapping defined inTable (4).

If at least one serving cell is configured with eIMTA, and if one ormore valid UL/DL configuration(s) in the UL/DL reconfiguration DCI witheIMTA-RNTI for at least one of the configured eIMTA cell(s)corresponding to a subframe for the PUCCH resource is not detected, anoffset value, or a separately configured PUCCH resource may also be usedto determine the PUCCH resource value from one of the four PUCCHresource values configured by higher layers. A UE 102 may assume thatthe same HARQ-ACK PUCCH resource value is transmitted on all PDCCHassignments used to determine the PUCCH resource values within thesubframe(s) n−k, where kεK.

For a PDSCH transmission on an SCell indicated by the detection of acorresponding EPDCCH, for M>1 and a PDSCH transmission only on the PCellindicated by the detection of a corresponding EPDCCH in subframen−k_(m), where k_(m)εK with the DAI value in the EPDCCH greater than 1or an EPDCCH indicating downlink SPS release in subframe n−k_(m), wherek_(m)εK with the DAI value in the EPDCCH greater than 1, the UE 102 mayuse PUCCH format 3, PUCCH resource n_(PUCCH) ^((3,{tilde over (p)}))(where the value of n_(PUCCH) ^((3,{tilde over (p)})) is determinedaccording to higher layer configuration and Table (4)) and the HARQ-ACKresource offset field in the DCI format of the corresponding EPDCCHassignment with a DAI value greater than 1 to determine the PUCCHresource value from one of the four PUCCH resource values configured byhigher layers, with the mapping defined in Table (4). If at least oneserving cell is configured with eIMTA, and one or more valid UL/DLconfiguration(s) in the UL/DL reconfiguration DCI with eIMTA-RNTI for atleast one of the configured eIMTA cell(s) corresponding to a subframefor the PUCCH resource is not detected, an offset value, or a separatelyconfigured PUCCH resource may also be used to determine the PUCCHresource value. A UE 102 may assume that the same HARQ-ACK PUCCHresource value is transmitted on all EPDCCH assignments used todetermine the PUCCH resource values within the subframe(s) n−k, wherekεK.

If the UL/DL configurations of all serving cells are the same, for aPDSCH transmission on the SCell indicated by the detection of acorresponding PDCCH/EPDCCH within subframe(s) n−k, where kεK, the UE 102may use PUCCH format 3, PUCCH resource n_(PUCCH) ^((3,{tilde over (p)}))(where the value of n_(PUCCH) ^((3,{tilde over (p)})) is determinedaccording to higher layer configuration and Table (4)) and the TPC fieldin the corresponding PDCCH/EPDCCH to determine the PUCCH resource valuefrom one of the four resource values configured by higher layers, withthe mapping defined in Table (4). If at least one serving cell isconfigured with eIMTA, and one or more valid UL/DL configuration(s) inthe UL/DL reconfiguration DCI with eIMTA-RNTI for at least one of theconfigured eIMTA cell(s) corresponding to a subframe for the PUCCHresource is not detected, then an offset value, or a separate configuredPUCCH resource may also be used to determine the PUCCH resource value.

For TDD UL/DL configurations 1-6, if a PDCCH corresponding to a PDSCH onthe PCell within subframe(s) n−k, where kεK, or a PDCCH indicatingdownlink SPS release within subframe(s) n−k, where kεK, is detected, theTPC field in the PDCCH with the DAI value greater than 1, and if atleast one serving cell is configured with eIMTA, and one or more validUL/DL configuration(s) in the UL/DL reconfiguration DCI with eIMTA-RNTIfor at least one of the configured eIMTA cell(s) corresponding to asubframe for the PUCCH resource is not detected, then an offset value,or a separately configured PUCCH resource may be used to determine thePUCCH resource value from one of the four resource values configured byhigher layers, with the mapping defined in Table (4). The UE 102 mayassume that the same HARQ-ACK PUCCH resource value is transmitted on allPDCCH assignments in the PCell and in each SCell that are used todetermine the PUCCH resource value within the subframe(s) n−k, wherekεK.

For TDD UL/DL configurations 1-6, if an EPDCCH corresponding to a PDSCHon the primary cell within subframe(s) n−k, where kεK, or an EPDCCHindicating downlink SPS release within subframe(s) n−k, where kεK, isdetected, the HARQ-ACK resource offset field in the DCI format of thecorresponding EPDCCH assignment with the DAI value greater than 1, andif at least one serving cell is configured with eIMTA, and one or morevalid UL/DL configuration(s) in the UL/DL reconfiguration DCI witheIMTA-RNTI for at least one of the configured eIMTA cell(s)corresponding to a subframe for the PUCCH resource is not detected, thenan offset value, or a separately configured PUCCH resource shall be usedto determine the PUCCH resource value from one of the four resourcevalues configured by higher layers, with the mapping defined in Table(4). The UE 102 may assume that the same HARQ-ACK PUCCH resource valueis transmitted on all EPDCCH assignments in the PCell and in each SCellthat are used to determine the PUCCH resource value within thesubframe(s) n−k, where kεK.

If the UL/DL configurations of at least two serving cells are different,for a PDSCH transmission on the SCell indicated by the detection of acorresponding PDCCH/EPDCCH within subframe(s) n−k, where kεK, the UE 102may use PUCCH format 3, PUCCH resource n_(PUCCH) ^((3,{tilde over (p)}))(where the value of n_(PUCCH) ^((3,{tilde over (p)})) is determinedaccording to higher layer configuration and Table (4)) and the TPC fieldin the corresponding PDCCH/EPDCCH to determine the PUCCH resource valuefrom one of the four resource values configured by higher layers, withthe mapping defined in Table (4). If at least one serving cell isconfigured with eIMTA, and one or more valid UL/DL configuration(s) inthe UL/DL reconfiguration DCI with eIMTA-RNTI for at least one of theconfigured eIMTA cell(s) corresponding to a subframe for the PUCCHresource is not detected, then an offset value, or a separatelyconfigured PUCCH resource may also be used to determine the PUCCHresource value.

For a UL/DL configuration of the PCell belonging to {1,2,3,4,5,6}, if aPDCCH corresponding to a PDSCH on the PCell within subframe(s) n−k,where kεK, or a PDCCH indicating downlink SPS release within subframe(s)n−k, where kεK, is detected, the TPC field in the PDCCH with the DAIvalue greater than 1 may be used to determine the PUCCH resource valuefrom one of the four resource values configured by higher layers, withthe mapping defined in Table (4). If at least one serving cell isconfigured with eIMTA, and one or more valid UL/DL configuration(s) inthe UL/DL reconfiguration DCI with eIMTA-RNTI for at least one of theconfigured eIMTA cell(s) corresponding to a subframe for the PUCCHresource is not detected, then an offset value, or a separatelyconfigured PUCCH resource may also be used to determine the PUCCHresource value. The UE 102 may assume that the same HARQ-ACK PUCCHresource value is transmitted on all PDCCH assignments in the PCell andin each SCell that are used to determine the PUCCH resource value withinthe subframe(s) n−k, where kεK.

Further, if the UL/DL configurations of at least two serving cells aredifferent, for a UL/DL configuration of the PCell belonging to{1,2,3,4,5,6}, if an EPDCCH corresponding to a PDSCH on the primary cellwithin subframe(s) n−k, where kεK, or an EPDCCH indicating downlink SPSrelease within subframe(s) n−k, where kεK, is detected, the HARQ-ACKresource offset field in the DCI format of the corresponding EPDCCHassignment with the DAI value greater than 1 may be used to determinethe PUCCH resource value from one of the four resource values configuredby higher layers, with the mapping defined in Table (4). If at least oneserving cell is configured with eIMTA, and valid UL/DL configuration(s)in the UL/DL reconfiguration DCI with eIMTA-RNTI for at least one of theconfigured eIMTA cell(s) corresponding to a subframe for the PUCCHresource is not detected, then an offset value, or a separatelyconfigured PUCCH resource may also be used to determine the PUCCHresource value. A UE 102 may assume that the same HARQ-ACK PUCCHresource value is transmitted on all EPDCCH assignments in the PCell andin each SCell that are used to determine the PUCCH resource value withinthe subframe(s) n−k, where kεK.

If valid UL/DL configuration in the reconfiguration DCI with eIMTA-RNTIon PCell CSS is not detected, HARQ-ACK fallback mode may also be used ifthere is only one PDSCH with a DAI value of 1 is detected on the PCell.Thus, if the eIMTA cell is a PCell, if there is only a SPS subframedetected, or if there is only one PDSCH detected with a DAI value of 1on the PCell only, the HARQ-ACK bits may be reported with PUCCH format1a/1b instead of PUCCH format 3. For a single PDSCH transmission only onthe PCell indicated by the detection of a corresponding PDCCH insubframe n−k_(m), where k_(m)εK, and for a TDD UL/DL configuration ofthe primary cell belonging to {1,2,3,4,5,6} the DAI value in the PDCCHis equal to 1, or for a PDCCH indicating downlink SPS release insubframe n−k_(m), where k_(m)εK, and for a TDD UL/DL configuration ofthe PCell belonging to {1,2,3,4,5,6} the DAI value in the PDCCH is equalto 1, the UE 102 may use PUCCH format 1a/1b and PUCCH resource n_(PUCCH)^((1,{tilde over (p)})) with n_(PUCCH) ^((1,{tilde over (p)}) ⁰⁾=(M−m−1)·N_(c)+m≦N_(c+1)−n_(CCE,m)+N_(PUCCH) ⁽¹⁾+δ or a separatelyconfigured PUCCH resource for antenna port p₀. In this case, n_(PUCCH)⁽¹⁾ is configured by higher layers, c is selected from {0, 1, 2, 3} suchthat N_(c)≦n_(CCE,m)<N_(c+1),

N_(c) = max {0, ⌊[N_(RB)^(DL) ⋅ (N_(sc)^(RB) ⋅ c − 4)]/36⌋},

and n_(CCE,m) is the number of the first CCE used for transmission ofthe corresponding PDCCH in subframe n−k_(m), where k_(m)εK. If at leastone serving cell is configured with eIMTA, and one or more valid UL/DLconfiguration(s) in the UL/DL reconfiguration DCI with eIMTA-RNTI for atleast one of the configured eIMTA cell(s) corresponding to a subframefor the PUCCH resource is not detected, then δ is a fixed, predefined orRRC configured offset, otherwise δ is 0. When a two antenna porttransmission is configured for PUCCH format 1a/1b, the PUCCH resourcefor antenna port p₁ is given by n_(PUCCH) ^((1,{tilde over (p)}) ¹⁾=n_(PUCCH) ^((1,{tilde over (p)}) ⁰ ⁾+1+δ.

For a single PDSCH transmission only on the PCell indicated by thedetection of a corresponding EPDCCH in subframe n−k_(m), where k_(m)εK,and for a TDD UL/DL configuration of the primary cell belonging to{1,2,3,4,5,6} the DAI value in the EPDCCH is equal to 1, or for a PDCCHindicating downlink SPS release in subframe n−k_(m), where k_(m)εK, andfor a TDD UL/DL configuration of the PCell belonging to {1,2,3,4,5,6}the DAI value in the EPDCCH is equal to 1, the UE 102 may use PUCCHformat 1a/1b and PUCCH resource n_(PUCCH) ^((1,{tilde over (p)})) givenby the following.

If EPDCCH-PRB-set q is configured for distributed transmission, then

$n_{PUCCH}^{({1,\overset{\sim}{p}})} = {n_{{ECCE},q} + {\sum\limits_{{i\; 1} = 0}^{m - 1}N_{{ECCE},q,{n - k_{i\; 1}}}} + \Delta_{ARO} + N_{{PUCCH},q}^{({e\; 1})} + \delta}$

or a separately configured PUCCH resource. If EPDCCH-PRB-set q isconfigured for localized transmission, then

$n_{PUCCH}^{({1,\overset{\sim}{p}})} = {{\left\lfloor \frac{n_{{ECCE},q}}{N_{RB}^{{ECCE},q}} \right\rfloor \cdot N_{RB}^{{ECCE},q}} + {\sum\limits_{{i\; 1} = 0}^{m - 1}N_{{ECCE},q,{n - k_{i\; 1}}}} + n^{\prime} + \Delta_{ARO} + N_{{PUCCH},q}^{({e\; 1})} + \delta}$

or a separately configured PUCCH resource.

In this case, n_(ECCE,q) is the number of the first ECCE (i.e. lowestECCE index used to construct the EPDCCH) used for transmission of thecorresponding DCI assignment in EPDCCH-PRB-set q in subframe n−k_(m),n_(PUCCH) ^((e1)) for EPDCCH-PRB-set q is configured by the higher layerparameter PUCCH-ResourceStartOffset-r11, and n′ is determined from theantenna port used for EPDCCH transmission in subframe n−k_(m).

If m=0, Δ_(ARO) is determined from the HARQ-ACK resource offset field inthe DCI format of the corresponding EPDCCH, as given in Table (5). Ifm>0, Δ_(ARO) is determined from the HARQ-ACK resource offset field inthe DCI format of the corresponding EPDCCH, as given in Table (6).

If the UE 102 is configured to monitor EPDCCH in subframe n−k_(i1),N_(ECCE,q,n−k) _(i1) is equal to the number of ECCEs in EPDCCH-PRB-set qconfigured for that UE 102 in subframe n−k_(i1). If the UE 102 is notconfigured to monitor EPDCCH in subframe n−k_(i1), N_(ECCE,q,n−k) _(i1)is equal to the number of ECCEs computed assuming EPDCCH-PRB-set q isconfigured for that UE 102 in subframe n−k_(i1).

For normal downlink CP, if subframe n−k_(i1) is a special subframe withspecial subframe configuration 0 or 5, N_(ECCE,q,n−k) _(i1) is equal to0. For extended downlink CP, if subframe n−k_(i1) is a special subframewith special subframe configuration 0 or 4 or 7, N_(ECCE,q,n−k) _(i1) isequal to 0. If at least one serving cell is configured with eIMTA, andone or more valid UL/DL configuration(s) in the UL/DL reconfigurationDCI with eIMTA-RNTI for at least one of the configured eIMTA cell(s)corresponding to a subframe for the PUCCH resource is not detected, δ isa fixed, predefined or RRC configured offset, otherwise δ is 0. When atwo antenna port transmission is configured for PUCCH format 1a/1b, thePUCCH resource for antenna port p₁ is given by n_(PUCCH)^((1,{tilde over (p)}) ¹ ⁾=n_(PUCCH) ^((1,{tilde over (p)}) ⁰ ⁾+1+δ.

For a single PDSCH transmission only on the PCell where there is not acorresponding PDCCH/EPDCCH detected within subframe(s) n−k, where kεK,and no PDCCH/EPDCCH indicating downlink SPS release within subframe(s)n−k, where kεK, the UE 102 may use PUCCH format 1a/1b and PUCCH resourcen_(PUCCH) ^((1,{tilde over (p)})), with the value of n_(PUCCH)^((1,{tilde over (p)})) determined according to higher layerconfiguration. If at least one serving cell is configured with eIMTA,and one or more valid UL/DL configuration(s) in the UL/DLreconfiguration DCI with eIMTA-RNTI for at least one of the configuredeIMTA cell(s) corresponding to a subframe for the PUCCH resource is notdetected, an offset δ may be applied to determine the PUCCH resource ora separately configured PUCCH resource may be used. For a UE 102configured for a two antenna port transmission for PUCCH format 1a/1b, aPUCCH resource value in Table (7) (maps to two PUCCH resources with thefirst PUCCH resource n_(PUCCH) ^((1,{tilde over (p)}) ⁰ ⁾ for antennaport p₀ and the second PUCCH resource n_(PUCCH) ^((1,{tilde over (p)}) ¹⁾ for antenna port p₁, otherwise, the PUCCH resource value maps to asingle PUCCH resource n_(PUCCH) ^((1,{tilde over (p)}) ⁰ ⁾ for antennaport p₀.

For M>1 and a PDSCH transmission only on the PCell where there is not acorresponding PDCCH detected within subframe(s) n−k, where kεK and anadditional PDSCH transmission only on the PCell indicated by thedetection of a corresponding PDCCH in subframe n−k_(m), where k_(m)εKwith the DAI value in the PDCCH equal to 1 or a PDCCH indicatingdownlink SPS release in subframe n−k_(m), where k_(m)εK with the DAIvalue in the PDCCH equal to 1, the UE 102 may transmit b(0),b(1) insubframe n using PUCCH format 1b on PUCCH resource n_(PUCCH) ⁽¹⁾selected from A PUCCH resources n_(PUCCH,i) ⁽¹⁾ where 0≦i≦A−1, accordingto Table (8) and Table (9) for A=2 and A=3, respectively. For a UE 102configured with a transmission mode that supports up to two transportblocks on the primary cell, A=3; otherwise, A=2.

The PUCCH resource n_(PUCCH,0) ⁽¹⁾ is determined according to higherlayer configuration and Table (7). The PUCCH resource n_(PUCCH,1) ⁽¹⁾ isdetermined as n_(PUCCH,1)⁽¹⁾=(M−m−1)·N_(c)+m·N_(c+1)+n_(CCE,m)+N_(PUCCH) ⁽¹⁾+δ or a separatelyconfigured PUCCH resource. N_(PUCCH) ⁽¹⁾ is configured by higher layers,c is selected from {0, 1, 2, 3} such that

N_(c) = max {0, ⌊[N_(RB)^(DL) ⋅ (N_(sc)^(RB) ⋅ c − 4)]/36⌋},

and n_(CCE,m) is the number of the first CCE used for transmission ofthe corresponding PDCCH in subframe n−k_(m), where k_(m)εK. If at leastone serving cell is configured with eIMTA, and one or more valid UL/DLconfiguration(s) in the UL/DL reconfiguration DCI with eIMTA-RNTI for atleast one of the configured eIMTA cell(s) corresponding to a subframefor the PUCCH resource is not detected, then δ is a fixed or predefinedor RRC configured offset, otherwise δ is 0.

For a UE 102 configured with a transmission mode that supports up to twotransport blocks on the PCell, the PUCCH resource n_(PUCCH,2) ⁽¹⁾ isdetermined as n_(PUCCH,2) ⁽¹⁾=n_(PUCCH,1) ⁽¹⁾+1+δ. HARQ-ACK(0) is theACK/NACK/DTX response for the PDSCH without a corresponding PDCCHdetected. HARQ-ACK(1) is the ACK/NACK/DTX response for the firsttransport block of the PDSCH indicated by the detection of acorresponding PDCCH for which the value of the DAI field in thecorresponding DCI format is equal to 1 or for the PDCCH indicatingdownlink SPS release for which the value of the DAI field in thecorresponding DCI format is equal to 1. HARQ-ACK(2) is the ACK/NACK/DTXresponse for the second transport block of the PDSCH indicated by thedetection of a corresponding PDCCH for which the value of the DAI fieldin the corresponding DCI format is equal to 1.

For M>1 and a PDSCH transmission only on the PCell where there is not acorresponding EPDCCH detected within subframe(s) n−k, where kεK, and anadditional PDSCH transmission only on the PCell indicated by thedetection of a corresponding EPDCCH in subframe n−k_(m), where k_(m)εK,with the DAI value in the EPDCCH equal to 1 or an EPDCCH indicatingdownlink SPS release in subframe n−k_(m), where k_(m)εK with the DAIvalue in the EPDCCH equal to 1, the UE 102 may transmit b(0),b(1) insubframe n using PUCCH format 1b on PUCCH resource n_(PUCCH) ⁽¹⁾selected from A PUCCH resources n_(PUCCH,i) ⁽¹⁾, where 0≦i≦A−1,according to Table (8) and Table (9) for A=2 and A=3, respectively. Fora UE 102 configured with a transmission mode that supports up to twotransport blocks on the primary cell, A=3; otherwise, A=2.

The PUCCH resource n_(PUCCH,0) ⁽¹⁾ is determined according to higherlayer configuration and Table (6). The PUCCH resource n_(PUCCH,1) ⁽¹⁾ isdetermined according to the following. If EPDCCH-PRB-set q is configuredfor distributed transmission, then

$n_{{PUCCH},1}^{(1)} = {n_{{ECCE},q} + {\sum\limits_{{i\; 1} = 0}^{m - 1}N_{{ECCE},q,{n - k_{i\; 1}}}} + \Delta_{ARO} + N_{{PUCCH},q}^{({e\; 1})} + \delta}$

or a separately configured PUCCH resource. If EPDCCH-PRB-set q isconfigured for localized transmission, then

$n_{{PUCCH},1}^{(1)} = {{\left\lfloor \frac{n_{{ECCE},q}}{N_{RB}^{{ECCE},q}} \right\rfloor \cdot N_{RB}^{{ECCE},q}} + {\sum\limits_{{i\; 1} = 0}^{m - 1}N_{{ECCE},q,{n - k_{i\; 1}}}} + n^{\prime} + \Delta_{ARO} + N_{{PUCCH},q}^{({e\; 1})} + \delta}$

or a separately configured PUCCH resource.

In this case, n_(ECCE,q) is the number of the first ECCE (i.e., lowestECCE index used to construct the EPDCCH) used for transmission of thecorresponding DCI assignment in EPDCCH-PRB-set q in subframe n−k_(m),N_(PUCCH) ^((e1)) for EPDCCH-PRB-set q is configured by the higher layerparameter PUCCH-ResourceStartOffset-r11, n′ is determined from theantenna port used for EPDCCH transmission in subframe n−k_(m).

If m=0, Δ_(ARO) is determined from the HARQ-ACK resource offset field inthe DCI format of the corresponding EPDCCH as given in Table (5). Ifm>0, Δ_(ARO) is determined from the HARQ-ACK resource offset field inthe DCI format of the corresponding EPDCCH as given in Table (6). If theUE 102 is configured to monitor EPDCCH in subframe n−k_(i1),N_(ECCE,q,n−k) _(i1) is equal to the number of ECCEs in EPDCCH-PRB-set qconfigured for that UE 102 in subframe n−k_(i1). If the UE 102 is notconfigured to monitor EPDCCH in subframe n−k_(i1), N_(ECCE,q,n−k) _(i1)is equal to the number of ECCEs computed assuming EPDCCH-PRB-set q isconfigured for that UE 102 in subframe n−k_(i1).

For normal downlink CP, if subframe n−k_(i1) is a special subframe withspecial subframe configuration 0 or 5, N_(ECCE,q,n−k) _(i1) is equal to0. For extended downlink CP, if subframe n−k_(i1) is a special subframewith special subframe configuration 0 or 4 or 7, N_(ECCE,q,n−k) _(i1) isequal to 0. If at least one serving cell is configured with eIMTA, andone or more valid UL/DL configuration(s) in the UL/DL reconfigurationDCI with eIMTA-RNTI for at least one of the configured eIMTA cell(s)corresponding to a subframe for the PUCCH resource is not detected, δ isa fixed or predefined or RRC configured offset, otherwise δ is 0.

For a UE 102 configured with a transmission mode that supports up to twotransport blocks on the primary cell, the PUCCH resource n_(PUCCH,2) ⁽¹⁾is determined as n_(PUCCH,2) ⁽¹⁾=n_(PUCCH,1) ⁽¹⁾+1+δ. HARQ-ACK(0) is theACK/NACK/DTX response for the PDSCH without a corresponding EPDCCHdetected. HARQ-ACK(1) is the ACK/NACK/DTX response for the firsttransport block of the PDSCH indicated by the detection of acorresponding EPDCCH for which the value of the DAI field in thecorresponding DCI format is equal to 1 or for the EPDCCH indicatingdownlink SPS release for which the value of the DAI field in thecorresponding DCI format is equal to 1. HARQ-ACK(2) is the ACK/NACK/DTXresponse for the second transport block of the PDSCH indicated by thedetection of a corresponding EPDCCH for which the value of the DAI fieldin the corresponding DCI format is equal to 1.

With another alternative implementation, the fallback HARQ-ACK to PUCCHformat 1a/1b may be the same as normal operation. Thus, the PUCCH format1a/1b resource may be determined by the PUCCH resource allocationmethods defined for eIMTA. Since in fallback mode operation, the UE 102monitors fixed DL and special subframes specified by SIB1 configuration,only the PUCCH resources for the fixed DL and special subframes in SIB1configuration are used and shared with Rel-8/9/10/11/12 UEs 102. Basedon the PUCCH resource used to carry the HARQ-ACK reporting, the eNB 160can identify missing PDSCH detections in other subframes, e.g. theflexible subframes. However, the eNB 160 cannot determine whether themisdetection is caused by channel conditions or misdetection of thereconfiguration DCI.

FIG. 9 illustrates various components that may be utilized in a UE 902.The UE 902 described in connection with FIG. 9 may be implemented inaccordance with the UE 102 described in connection with FIG. 1. The UE902 includes a processor 963 that controls operation of the UE 902. Theprocessor 963 may also be referred to as a central processing unit(CPU). Memory 969, which may include read-only memory (ROM), randomaccess memory (RAM), a combination of the two or any type of device thatmay store information, provides instructions 965 a and data 967 a to theprocessor 963. A portion of the memory 969 may also include non-volatilerandom access memory (NVRAM). Instructions 965 b and data 967 b may alsoreside in the processor 963. Instructions 965 b and/or data 967 b loadedinto the processor 963 may also include instructions 965 a and/or data967 a from memory 969 that were loaded for execution or processing bythe processor 963. The instructions 965 b may be executed by theprocessor 963 to implement one or more of the methods 200, 600, 700 and800 described above.

The UE 902 may also include a housing that contains one or moretransmitters 958 and one or more receivers 920 to allow transmission andreception of data. The transmitter(s) 958 and receiver(s) 920 may becombined into one or more transceivers 918. One or more antennas 922 a-nare attached to the housing and electrically coupled to the transceiver918.

The various components of the UE 902 are coupled together by a bussystem 971, which may include a power bus, a control signal bus and astatus signal bus, in addition to a data bus. However, for the sake ofclarity, the various buses are illustrated in FIG. 9 as the bus system971. The UE 902 may also include a digital signal processor (DSP) 973for use in processing signals. The UE 902 may also include acommunications interface 975 that provides user access to the functionsof the UE 902. The UE 902 illustrated in FIG. 9 is a functional blockdiagram rather than a listing of specific components.

FIG. 10 illustrates various components that may be utilized in an eNB1060. The eNB 1060 described in connection with FIG. 10 may beimplemented in accordance with the eNB 160 described in connection withFIG. 1. The eNB 1060 includes a processor 1077 that controls operationof the eNB 1060. The processor 1077 may also be referred to as a centralprocessing unit (CPU). Memory 1083, which may include read-only memory(ROM), random access memory (RAM), a combination of the two or any typeof device that may store information, provides instructions 1079 a anddata 1081 a to the processor 1077. A portion of the memory 1083 may alsoinclude non-volatile random access memory (NVRAM). Instructions 1079 band data 1081 b may also reside in the processor 1077. Instructions 1079b and/or data 1081 b loaded into the processor 1077 may also includeinstructions 1079 a and/or data 1081 a from memory 1083 that were loadedfor execution or processing by the processor 1077. The instructions 1079b may be executed by the processor 1077 to implement method 300described above.

The eNB 1060 may also include a housing that contains one or moretransmitters 1017 and one or more receivers 1078 to allow transmissionand reception of data. The transmitter(s) 1017 and receiver(s) 1078 maybe combined into one or more transceivers 1076. One or more antennas1080 a-n are attached to the housing and electrically coupled to thetransceiver 1076.

The various components of the eNB 1060 are coupled together by a bussystem 1085, which may include a power bus, a control signal bus and astatus signal bus, in addition to a data bus. However, for the sake ofclarity, the various buses are illustrated in FIG. 10 as the bus system1085. The eNB 1060 may also include a digital signal processor (DSP)1087 for use in processing signals. The eNB 1060 may also include acommunications interface 1089 that provides user access to the functionsof the eNB 1060. The eNB 1060 illustrated in FIG. 10 is a functionalblock diagram rather than a listing of specific components.

FIG. 11 is a block diagram illustrating one configuration of a UE 1102in which systems and methods for feedback reporting may be implemented.The UE 1102 includes transmit means 1158, receive means 1120 and controlmeans 1124. The transmit means 1158, receive means 1120 and controlmeans 1124 may be configured to perform one or more of the functionsdescribed in connection with FIG. 2, FIG. 6, FIG. 7, FIG. 8 and FIG. 9above. FIG. 9 above illustrates one example of a concrete apparatusstructure of FIG. 11. Other various structures may be implemented torealize one or more of the functions of FIG. 2, FIG. 6, FIG. 7, FIG. 8and FIG. 9. For example, a DSP may be realized by software.

FIG. 12 is a block diagram illustrating one configuration of an eNB 1260in which systems and methods for feedback reporting may be implemented.The eNB 1260 includes transmit means 1217, receive means 1278 andcontrol means 1282. The transmit means 1217, receive means 1278 andcontrol means 1282 may be configured to perform one or more of thefunctions described in connection with FIG. 3 and FIG. 10 above. FIG. 10above illustrates one example of a concrete apparatus structure of FIG.12. Other various structures may be implemented to realize one or moreof the functions of FIG. 3 and FIG. 10. For example, a DSP may berealized by software.

The term “computer-readable medium” refers to any available medium thatcan be accessed by a computer or a processor. The term“computer-readable medium,” as used herein, may denote a computer-and/or processor-readable medium that is non-transitory and tangible. Byway of example, and not limitation, a computer-readable orprocessor-readable medium may comprise RAM, ROM, Electrically ErasableProgrammable Read-Only Memory (EEPROM), Compact Disc Read-Only Memory(CD-ROM) or other optical disk storage, magnetic disk storage or othermagnetic storage devices, or any other medium that can be used to carryor store desired program code in the form of instructions or datastructures and that can be accessed by a computer or processor. Disk anddisc, as used herein, includes compact disc (CD), laser disc, opticaldisc, digital versatile disc (DVD), floppy disk and Blu-ray® disc wheredisks usually reproduce data magnetically, while discs reproduce dataoptically with lasers.

It should be noted that one or more of the methods described herein maybe implemented in and/or performed using hardware. For example, one ormore of the methods described herein may be implemented in and/orrealized using a chipset, an application-specific integrated circuit(ASIC), a large-scale integrated circuit (LSI) or integrated circuit,etc.

Each of the methods disclosed herein comprises one or more steps oractions for achieving the described method. The method steps and/oractions may be interchanged with one another and/or combined into asingle step without departing from the scope of the claims. In otherwords, unless a specific order of steps or actions is required forproper operation of the method that is being described, the order and/oruse of specific steps and/or actions may be modified without departingfrom the scope of the claims.

It is to be understood that the claims are not limited to the preciseconfiguration and components illustrated above. Various modifications,changes and variations may be made in the arrangement, operation anddetails of the systems, methods, and apparatus described herein withoutdeparting from the scope of the claims.

What is claimed is:
 1. A user equipment (UE), comprising: a processor;and memory in electronic communication with the processor, whereininstructions stored in the memory are executable to: decode anuplink/downlink (UL/DL) reconfiguration downlink control information(DCI) with an enhanced interference mitigation with traffic adaptation(eIMTA)-radio network temporary identifier (RNTI) on a physical downlinkcontrol channel (PDCCH); determine if one or more valid UL/DLconfigurations in the UL/DL reconfiguration DCI with eIMTA-RNTI for allconfigured eIMTA cells are received; determine if physical uplinkcontrol channel (PUCCH) format 3 is configured; determine a PUCCHresource for physical downlink shared channel (PDSCH) hybrid automaticrepeat request acknowledgement/negative acknowledgement (HARQ-ACK)reporting based on whether valid UL/DL configurations in the UL/DLreconfiguration DCI with eIMTA-RNTI for all of the configured eIMTAcells corresponding to a subframe for the PUCCH resource are received;and send PDSCH HARQ-ACK information on the selected PUCCH resource in anuplink subframe.
 2. The UE of claim 1, wherein if PUCCH format 3 isconfigured and valid UL/DL configurations in the UL/DL reconfigurationDCI with eIMTA-RNTI for all of the configured eIMTA cells correspondingto a subframe for the PUCCH resource are received, then the instructionsare further executable to: determine the PDSCH HARQ-ACK informationbased on at least one of a DL subframe and a special subframe accordingto the UL/DL configuration in the UL/DL reconfiguration DCI in a DLassociation set for a given UL subframe of each configured eIMTA cell.3. The UE of claim 1, wherein if PUCCH format 3 is configured and one ormore valid UL/DL configurations in the UL/DL reconfiguration DCI witheIMTA-RNTI for at least one of the one or more configured eIMTA cellscorresponding to a subframe for the PUCCH resource is not received, thenthe instructions are further executable to: determine the PDSCH HARQ-ACKinformation based on at least one of a DL subframe and a specialsubframe according to a system information block type 1 (SIB1)configuration in a DL association set according to a DL HARQ referenceconfiguration for a given UL subframe of each configured eIMTA cell,wherein the SIB1 configuration comprises a UL/DL configuration in SIB1signaling or RadioResourceConfigCommon signaling when a configured eIMTAcell is a primary cell (PCell), and wherein the SIB1 configurationcomprises a UL/DL configuration in RadioResourceConfigCommonSCell-r10signaling when a configured eIMTA cell is a secondary cell (SCell). 4.The UE of claim 1, wherein if PUCCH format 3 is configured and a validUL/DL configuration in the UL/DL reconfiguration DCI with eIMTA-RNTI forat least one configured eIMTA cell corresponding to a subframe for thePUCCH resource is not received, then the instructions are furtherexecutable to: determine the PDSCH HARQ-ACK information based on a DLassociation set according to a DL HARQ reference configuration for agiven UL subframe of each configured eIMTA cell.
 5. The UE of claim 1,wherein if valid UL/DL configurations in the UL/DL reconfiguration DCIwith eIMTA-RNTI of all configured eIMTA cells corresponding to asubframe for the PUCCH resource are received, then the instructionsexecutable to determine the PUCCH resource comprise instructionsexecutable to determine the PUCCH resource based on at least one of aTransmitter Power Control (TPC) field and an acknowledgment resourceoffset (ARO).
 6. The UE of claim 5, wherein: if a PDSCH is detected on asecondary cell (SCell) in a DL assignment by PDCCH/enhanced physicaldownlink control channel (EPDCCH), or a downlink assignment index (DAI)value is greater than 1 in a detected PDCCH on a primary cell (PCell),then the instructions are further executable to: determine a PUCCHformat 3 resource based on a Transmitter Power Control (TPC) field in aPDCCH/EPDCCH assignment with a DAI value greater than 1; if there is noPDSCH detected on an SCell and a DAI value is greater than 1 in adetected EPDCCH on a PCell, then the instructions are further executableto: determine a PUCCH format 3 resource based on a HARQ-ACK resourceoffset field in a DCI format of a corresponding EPDCCH assignment with aDAI value greater than 1; and if there is only one PDSCH detected with aDAI value of 1, excluding semi-persistent scheduling (SPS) on a PCell,then the instructions are further executable to: determine a PUCCHformat 1a/1b resource based on the number of control channel elements(CCE).
 7. The UE of claim 1, wherein if at least one valid UL/DLconfiguration in the UL/DL reconfiguration DCI with eIMTA-RNTI for atleast one configured eIMTA cell corresponding to a subframe for thePUCCH resource is not received, then the instructions executable todetermine the PUCCH resource comprise instructions executable todetermine the PUCCH resource based on at least one of a predefinedoffset or a separate PUCCH resource.
 8. The UE of claim 7, wherein: if aPDSCH is detected on a secondary cell (SCell) in a DL assignment byPDCCH/EPDCCH, or a downlink assignment index (DAI) value is greater than1 in a detected PDCCH on a primary cell (PCell), then the instructionsare further executable to: determine a PUCCH format 3 resource based ona predefined offset or a separate PUCCH resource and a Transmitter PowerControl (TPC) field in a PDCCH/EPDCCH assignment with a DAI valuegreater than 1; if there is no PDSCH detected on an SCell and a DAIvalue is greater than 1 in a detected EPDCCH on a PCell, then theinstructions are further executable to: determine a PUCCH format 3resource based on at least one of a predefined offset or a separatePUCCH resource and a HARQ-ACK resource offset field in a DCI format of acorresponding EPDCCH assignment with a DAI value greater than 1; and ifthere is only one PDSCH detected with a DAI value of 1, excludingsemi-persistent scheduling (SPS) on a PCell, then the instructions arefurther executable to: determine a PUCCH format 1a/1b resource based onthe number of control channel elements (CCE).
 9. The UE of claim 1,wherein if valid UL/DL configurations in the UL/DL reconfiguration DCIwith eIMTA-RNTI for all of the configured eIMTA cells corresponding to asubframe for the PUCCH resource are received, then the instructionsexecutable to determine the PUCCH resource further comprise instructionsexecutable to determine the PUCCH resource based on at least one of apredefined offset or a separate PUCCH resource.
 10. The UE of claim 9,wherein: if a PDSCH is detected on a secondary cell (SCell) in a DLassignment by PDCCH/EPDCCH, or a downlink assignment index (DAI) valueis greater than 1 in a detected PDCCH on a primary cell (PCell), thenthe instructions are further executable to: determine a PUCCH format 3resource based on at least one of a predefined offset or a separatePUCCH resource and a Transmitter Power Control (TPC) field in aPDCCH/EPDCCH assignment with a DAI value greater than 1; if there is noPDSCH detected on an SCell and a DAI value is greater than 1 in adetected EPDCCH on a PCell, then the instructions are further executableto: determine a PUCCH format 3 resource based on at least one of apredefined offset or a separate PUCCH resource and a HARQ-ACK resourceoffset field in a DCI format of a corresponding EPDCCH assignment with aDAI value greater than 1; and if there is only one PDSCH detected with aDAI value of 1, excluding semi-persistent scheduling (SPS), on a PCell,then the instructions are further executable to: determine a PUCCHformat 1a/1b resource based on the number of control channel elements(CCE).
 11. The UE of claim 1, wherein if at least one valid UL/DLconfiguration in the UL/DL reconfiguration DCI with eIMTA-RNTI for atleast one configured eIMTA cell corresponding to a subframe for thePUCCH resource is not received, then the instructions executable todetermine the PUCCH resource comprise instructions executable todetermine the PUCCH resource based on at least one of a TransmitterPower Control (TPC) field and an acknowledgment resource offset (ARO).12. The UE of claim 11, wherein: if a PDSCH is detected on a secondarycell (SCell) in a DL assignment by PDCCH/EPDCCH or a downlink assignmentindex (DAI) value is greater than 1 in a detected PDCCH on a primarycell (PCell), then the instructions are further executable to: determinea PUCCH format 3 resource based on a Transmitter Power Control (TPC)field in a PDCCH/EPDCCH assignment with a DAI value greater than 1; ifthere is no PDSCH detected on a secondary cell (SCell) and a DAI valuegreater than 1 in a detected EPDCCH on a PCell, then the instructionsare further executable to: determine a PUCCH format 3 resource based ona HARQ-ACK resource offset field in a DCI format of a correspondingEPDCCH assignment with a DAI value greater than 1; and if there is onlyone PDSCH detected with a DAI value of 1, excluding semi-persistentscheduling (SPS), on a PCell, then the instructions are furtherexecutable to: determine a PUCCH format 1a/1b resource based on thenumber of control channel elements (CCE).
 13. An evolved node B (eNB),comprising: a processor; and memory in electronic communication with theprocessor, wherein instructions stored in the memory are executable to:transmit, to a user equipment (UE), uplink/downlink (UL/DL)reconfiguration downlink control information (DCI) with an enhancedinterference mitigation with traffic adaptation (eIMTA)-radio networktemporary identifier (RNTI) on a physical downlink control channel(PDCCH); assume that the UE determines if one or more valid UL/DLconfigurations in the UL/DL reconfiguration DCI with eIMTA-RNTI for allof the configured eIMTA cells are received; assume that the UEdetermines if physical uplink control channel (PUCCH) format 3 isconfigured; assume that the UE determines a PUCCH resource for physicaldownlink shared channel (PDSCH) hybrid automatic repeat requestacknowledgement/negative acknowledgement (HARQ-ACK) reporting based onwhether valid UL/DL configurations in the UL/DL reconfiguration DCI witheIMTA-RNTI for all of the configured eIMTA cells corresponding to asubframe for the PUCCH resource is received; and monitor potential PUCCHresources and receive PDSCH HARQ-ACK information on the detected PUCCHresource in an uplink subframe.
 14. The eNB of claim 13, wherein ifPUCCH format 3 is configured and valid UL/DL configurations in the UL/DLreconfiguration DCI with eIMTA-RNTI for all of the configured eIMTAcells corresponding to a subframe for the PUCCH resource are received bythe UE, then the instructions are further executable to: assume that theUE determines the PDSCH HARQ-ACK information based on at least one of aDL subframe and a special subframe according to the UL/DL configurationin the UL/DL reconfiguration DCI in a DL association set for a given ULsubframe of each configured eIMTA cell.
 15. The eNB of claim 13, whereinif PUCCH format 3 is configured and one or more valid UL/DLconfigurations in the UL/DL reconfiguration DCI with eIMTA-RNTI for atleast one of the one or more configured eIMTA cells corresponding to asubframe for the PUCCH resource is not received by the UE, then theinstructions are further executable to: assume that the UE determinesthe PDSCH HARQ-ACK information based on at least one of a DL subframeand a special subframe according to a system information block type 1(SIB1) configuration in a DL association set according to a DL HARQreference configuration for a given UL subframe of each configured eIMTAcell, wherein the SIB1 configuration comprises a UL/DL configuration inSIB1 signaling or RadioResourceConfigCommon signaling when a configuredeIMTA cell is a primary cell (PCell), and wherein the SIB1 configurationcomprises a UL/DL configuration in RadioResourceConfigCommonSCell-r10signaling when a configured eIMTA cell is a secondary cell (SCell). 16.The eNB of claim 13, wherein if PUCCH format 3 is configured and a validUL/DL configuration in the UL/DL reconfiguration DCI with eIMTA-RNTI forat least one configured eIMTA cell corresponding to a subframe for thePUCCH resource is not received by the UE, then the instructions arefurther executable to: assume that the UE determines the PDSCH HARQ-ACKinformation based on a DL association set according to a DL HARQreference configuration for a given UL subframe of each configured eIMTAcell.
 17. The eNB of claim 13, wherein if valid UL/DL configurations inthe UL/DL reconfiguration DCI with eIMTA-RNTI of all configured eIMTAcells corresponding to a subframe for the PUCCH resource are received bythe UE, then the instructions executable to assume that the UEdetermines the PUCCH resource comprise instructions executable to assumethat the UE determines the PUCCH resource based on at least one of aTransmitter Power Control (TPC) field and an acknowledgment resourceoffset (ARO).
 18. The eNB of claim 17, wherein: if a PDSCH is detected,by the UE, on a secondary cell (SCell) in a DL assignment byPDCCH/enhanced physical downlink control channel (EPDCCH), or a downlinkassignment index (DAI) value is greater than 1 in a detected PDCCH on aprimary cell (PCell), then the instructions are further executable to:assume that the UE determines a PUCCH format 3 resource based on aTransmitter Power Control (TPC) field in a PDCCH/EPDCCH assignment witha DAI value greater than 1; if there is no PDSCH detected, by the UE, onan SCell and a DAI value is greater than 1 in a detected EPDCCH on aPCell, then the instructions are further executable to: assume that theUE determines a PUCCH format 3 resource based on a HARQ-ACK resourceoffset field in a DCI format of a corresponding EPDCCH assignment with aDAI value greater than 1; and if there is only one PDSCH detected, bythe UE, with a DAI value of 1, excluding semi-persistent scheduling(SPS) on a PCell, then the instructions are further executable to:assume that the UE determines a PUCCH format 1a/1b resource based on thenumber of control channel elements (CCE).
 19. The eNB of claim 13,wherein if at least one valid UL/DL configuration in the UL/DLreconfiguration DCI with eIMTA-RNTI for at least one configured eIMTAcell corresponding to a subframe for the PUCCH resource is not receivedby the UE, then the instructions executable to assume that the UEdetermines the PUCCH resource comprise instructions executable to assumethat the UE determines the PUCCH resource based on at least one of apredefined offset or a separate PUCCH resource.
 20. The eNB of claim 19,wherein: if a PDSCH is detected, by the UE, on a secondary cell (SCell)in a DL assignment by PDCCH/EPDCCH, or a downlink assignment index (DAI)value is greater than 1 in a detected PDCCH on a primary cell (PCell),then the instructions are further executable to: assume that the UEdetermines a PUCCH format 3 resource based on a predefined offset or aseparate PUCCH resource and a Transmitter Power Control (TPC) field in aPDCCH/EPDCCH assignment with a DAI value greater than 1; if there is noPDSCH detected, by the UE, on an SCell and a DAI value is greater than 1in a detected EPDCCH on a PCell, then the instructions are furtherexecutable to: assume that the UE determines a PUCCH format 3 resourcebased on at least one of a predefined offset or a separate PUCCHresource and a HARQ-ACK resource offset field in a DCI format of acorresponding EPDCCH assignment with a DAI value greater than 1; and ifthere is only one PDSCH detected, by the UE, with a DAI value of 1,excluding semi-persistent scheduling (SPS) on a PCell, then theinstructions are further executable to: assume that the UE determines aPUCCH format 1a/1b resource based on the number of control channelelements (CCE).
 21. A method performed by a user equipment (UE),comprising: decoding an uplink/downlink (UL/DL) reconfiguration downlinkcontrol information (DCI) with an enhanced interference mitigation withtraffic adaptation (eIMTA)-radio network temporary identifier (RNTI) ona physical downlink control channel (PDCCH); determining if one or morevalid UL/DL configurations in the UL/DL reconfiguration DCI witheIMTA-RNTI for all configured eIMTA cells are received; determining ifphysical uplink control channel (PUCCH) format 3 is configured;determining a PUCCH resource for physical downlink shared channel(PDSCH) hybrid automatic repeat request acknowledgement/negativeacknowledgement (HARQ-ACK) reporting based on whether valid UL/DLconfigurations in the UL/DL reconfiguration DCI with eIMTA-RNTI for allof the configured eIMTA cells corresponding to a subframe for the PUCCHresource are received; and sending PDSCH HARQ-ACK information on theselected PUCCH resource in an uplink subframe.
 22. The method of claim21, wherein if PUCCH format 3 is configured and one or more valid UL/DLconfigurations in the UL/DL reconfiguration DCI with eIMTA-RNTI for atleast one of the one or more configured eIMTA cells corresponding to asubframe for the PUCCH resource is not received, then the method furthercomprises: determining the PDSCH HARQ-ACK information based on at leastone of a DL subframe and a special subframe according to a systeminformation block type 1 (SIB1) configuration in a DL association setaccording to a DL HARQ reference configuration for a given UL subframeof each configured eIMTA cell, wherein the SIB1 configuration comprisesa UL/DL configuration in SIB1 signaling or RadioResourceConfigCommonsignaling when a configured eIMTA cell is a primary cell (PCell), andwherein the SIB1 configuration comprises a UL/DL configuration inRadioResourceConfigCommonSCell-r10 signaling when a configured eIMTAcell is a secondary cell (SCell).
 23. The method of claim 21, wherein ifPUCCH format 3 is configured and a valid UL/DL configuration in theUL/DL reconfiguration DCI with eIMTA-RNTI for at least one configuredeIMTA cell corresponding to a subframe for the PUCCH resource is notreceived, then the method further comprises: determining the PDSCHHARQ-ACK information based on a DL association set according to a DLHARQ reference configuration for a given UL subframe of each configuredeIMTA cell.
 24. The method of claim 21, wherein if valid UL/DLconfigurations in the UL/DL reconfiguration DCI with eIMTA-RNTI of allconfigured eIMTA cells corresponding to a subframe for the PUCCHresource are received, then determining the PUCCH resource comprisesdetermining the PUCCH resource based on at least one of a TransmitterPower Control (TPC) field and an acknowledgment resource offset (ARO).25. The method of claim 24, wherein: if a PDSCH is detected on asecondary cell (SCell) in a DL assignment by PDCCH/enhanced physicaldownlink control channel (EPDCCH), or a downlink assignment index (DAI)value is greater than 1 in a detected PDCCH on a primary cell (PCell),then the method further comprises: determining a PUCCH format 3 resourcebased on a Transmitter Power Control (TPC) field in a PDCCH/EPDCCHassignment with a DAI value greater than 1; if there is no PDSCHdetected on an SCell and a DAI value is greater than 1 in a detectedEPDCCH on a PCell, then the method further comprises: determining aPUCCH format 3 resource based on a HARQ-ACK resource offset field in aDCI format of a corresponding EPDCCH assignment with a DAI value greaterthan 1; and if there is only one PDSCH detected with a DAI value of 1,excluding semi-persistent scheduling (SPS) on a PCell, then the methodfurther comprises: determining a PUCCH format 1a/1b resource based onthe number of control channel elements (CCE).
 26. The method of claim21, wherein if at least one valid UL/DL configuration in the UL/DLreconfiguration DCI with eIMTA-RNTI for at least one configured eIMTAcell corresponding to a subframe for the PUCCH resource is not received,then determining the PUCCH resource comprises determining the PUCCHresource based on at least one of a predefined offset or a separatePUCCH resource.
 27. The method of claim 26, wherein: if a PDSCH isdetected on a secondary cell (SCell) in a DL assignment by PDCCH/EPDCCH,or a downlink assignment index (DAI) value is greater than 1 in adetected PDCCH on a primary cell (PCell), then the method furthercomprises: determining a PUCCH format 3 resource based on a predefinedoffset or a separate PUCCH resource and a Transmitter Power Control(TPC) field in a PDCCH/EPDCCH assignment with a DAI value greater than1; if there is no PDSCH detected on an SCell and a DAI value is greaterthan 1 in a detected EPDCCH on a PCell, then the method furthercomprises: determining a PUCCH format 3 resource based on at least oneof a predefined offset or a separate PUCCH resource and a HARQ-ACKresource offset field in a DCI format of a corresponding EPDCCHassignment with a DAI value greater than 1; and if there is only onePDSCH detected with a DAI value of 1, excluding semi-persistentscheduling (SPS) on a PCell, then the method further comprises:determining a PUCCH format 1a/1b resource based on the number of controlchannel elements (CCE).
 28. A method performed by an evolved node B(eNB), comprising: transmitting, to a user equipment (UE),uplink/downlink (UL/DL) reconfiguration downlink control information(DCI) with an enhanced interference mitigation with traffic adaptation(eIMTA)-radio network temporary identifier (RNTI) on a physical downlinkcontrol channel (PDCCH); assuming that the UE determines if one or morevalid UL/DL configurations in the UL/DL reconfiguration DCI witheIMTA-RNTI for all of the configured eIMTA cells are received; assumingthat the UE determines if physical uplink control channel (PUCCH) format3 is configured; assuming that the UE determines a PUCCH resource forphysical downlink shared channel (PDSCH) hybrid automatic repeat requestacknowledgement/negative acknowledgement (HARQ-ACK) reporting based onwhether valid UL/DL configurations in the UL/DL reconfiguration DCI witheIMTA-RNTI for all of the configured eIMTA cells corresponding to asubframe for the PUCCH resource is received; and monitoring potentialPUCCH resources and receiving PDSCH HARQ-ACK information on the detectedPUCCH resource in an uplink subframe.
 29. The method of claim 28,wherein if valid UL/DL configurations in the UL/DL reconfiguration DCIwith eIMTA-RNTI of all configured eIMTA cells corresponding to asubframe for the PUCCH resource are received by the UE, then assumingthat the UE determines the PUCCH resource comprises assuming that the UEdetermines the PUCCH resource based on at least one of a TransmitterPower Control (TPC) field and an acknowledgment resource offset (ARO).30. The method of claim 28, wherein if at least one valid UL/DLconfiguration in the UL/DL reconfiguration DCI with eIMTA-RNTI for atleast one configured eIMTA cell corresponding to a subframe for thePUCCH resource is not received by the UE, then assuming that the UEdetermines the PUCCH resource comprises assuming that the UE determinesthe PUCCH resource based on at least one of a predefined offset or aseparate PUCCH resource.